[DeTomaso] Comments about engine build welcome

[Christopher Kimball]

Dear Dan,

Wow--what a ton of information!

I appreciate it, and will share it all with the builder.  My guess is my budget may or may not allow all the recommendations...

Thanks again,

Chris



> Date: Sat, 10 Jan 2009 17:45:45 -0600
> From: daniel.c.jones2 at gmail.com
> To: chrisvkimball at msn.com
> Subject: Re: [DeTomaso] Comments about engine build welcome
> CC: detomaso at realbig.com
> 
> > The cam is meant for 351 cu-in.  How should the cam specs be changed to
> > better work with the 408 cu-in displacement?
> 
> If a cam is optimized for 351 CID, then you would want to narrow the lobe
> separation angle approximately 1 degree for every 16 degrees of displacement
> increase.  In your case, that would be 3 or 4 degrees.  However, your cam is
> probably not optimized for 351 CID and canted valve heads, For the 351C I'm
> currently dyno testing, the optimum (theoretical) LSA is 107 degrees.  An
> optimal angle for a 408C would be maybe 104 degrees.  You won't seen many
> off-the-shelf cams with a lobe center that narrow, though some circle track
> cams are ground with tight LSA's (104 to 106 degrees).  A very tight lobe
> separation angle needs a very efficient exhaust to keep the reversion to an
> acceptable degree.
> 
> > Suggested RPM Limit: 6000
> 
> At what RPM do you want the HP to peak?  In a 408C, the overlap of the cam
> you've specified would peak at 5000 RPM, perhaps less, and the engine would
> stop making power well before your 6000 RPM limit.  In my testing of a
> 408C with another 10 degrees of duration:
> 
> 232/236 degrees @ 0.050" lift (294/298 @ 0.004"), 0.609"/0.621" lift, 108 LSA
> Crane Cams grind number (custom): HR-232/352-2S-8
> 
> the engine peaked in the 5500 to 5600 RPM range, no matter what the intake,
> carb or headers we tried.  In a 10:1 compression 408C with ported iron 4V
> heads (322 CFM at 0.6" lift) and a Holley Strip Dominator intake, it made
> over 480 HP through the mufflers on a dyno that is known to read 5% low
> compared to the calibrated Engine Masters dynos.  Taking that into account,
> the engine made over 500 HP corrected.  A second 408C with more cam (peaked
> made 525 HP (550+ HP taking into account the dyno calibration), even though
> its heads were not as good as our earlier 408C.  Best shift point is typically
> around 400 to 500 RPM beyond power peak which would be right at your 6000 RPM
> limit.  Personally, I wouldn't use anything less than that can in a 408C.
> Depending upon the heads and intake you settle on, I could spec a variation
> on the above specs using some lobes that seem to hold on better past power
> peak (it'll hold the power peak for a wider RPM before falling off).
> 
> Be aware that Comp's hydraulic rollers are ground on a reduced base circle
> austempered ductile iron core.  The Crane and Reed hydraulic rollers we've
> used on the dyno engines used standard base circle steel cam cores.  It
> varies from block-to-block but there can be lifter issues with hydraulic
> roller cams in 351C blocks.  A friend ran into interference issues with a
> Comp hydraulic roller using OEM Ford lifters (dog bone and spider retention).
> He had to use the more expensive Crane link bar lifters.  On our current
> 351C dyno engine, the lifter bores have a chamfer that exposes the oil feed
> hole on OEM Ford hydraulic lifters.  We also tried the new Comp cams link
> bar lifters which look very nice and use their solid roller lifter body
> but they had the oil feed hole in the same place as the Ford lifters.
> The fix was a set of the Crane link bar lifters which have the oil hole
> placed lower.  Our previous dyno 351C did not have either of these probblems
> and accepted a standard base circle cam with either the Ford or the Crane
> link bar lifters (and presumably the Comps though we didn't test them).
> Since this varies from block-to-block, you may want to check clearance
> before assembling the short block.  The first problem can sometimes be
> fied by grinding on the block (a local machine shop has a little fixture
> they use to clearance 351C blocks being fitted with hydraulic roller cams).
> and the second can be fixed by bushing the lifter bores.  Either is easy on
> a disassembled engine but on an assembled engine the Crane link bars might
> be the best way to go.  The Crane link bar lifters have worked in all the
> 351C blocks we've tried, with reduced or standard base circle cams but are
> several hundred dollars more expensive than the OEM Ford lifters.  The Comps
> are more expensive still.
> 
> Whatever cam core you decide on, make sure your distributor gear is
> compatible. I made a lengthy post on the gear options a while back.
> 
> > Timing Set:  Pro Gear true roller.
> 
> Beware if that has the Rolon chain from India.  When Barry Rabotnick was at
> Speed-Pro, they had a bunch of off-shore companies tryingto become suppliers,
> so they piggy-backed some timing chain and sprocket testing onan OE bearing
> durability test.  The Rolon chain from India cost them the test motor test
> a couple times when they failed before the test was completed.  A summary of
> the test results for the chains is listed below.  Speed Pro ended up using
> Dynagear sprockets and Morse chain but had some quality control issues then
> Dynagear went out of business.  After that they sourced the high end Cloyes
> sets (which used French Renold and German Iwis chain) and the quality control
> complaints went away.  The Ford Motorsport 351C timing sets I've examined all
> used the French Renod chain.  While there are many companies who sell timing
> sets, most do not make their own product.  They source the gear and chain from
> other companies and can change suppliers without warning.  The sprockets come
> from Rollmaster (Australia), SA Gear (US but not the best quality) and Cloyes
> (US, not pretty but good quality).  Avon also makes some sprockets but sources
> others.  Dynagear (US) used to make sprockets but went out of business.  A
> bunch of the performance aftermarket companies are selling poor quality chain
> from India (Rolon), along with sprockets from pretty gears from Australia
> (Rollmaster, J.P Performance) or SA gears.
> 
> Chain durability testing summary:
> 
>  Iwis (German) - looks very nice but was not tested, but has excellent
>                 reputation as OE supplier, used in high end Rollmaster
>                 and some high end Cloyes sets
>  Cloyes (US) - tested OK
>  Renold (France) - tested excellent, used in most high end Cloyes sets
>                    but not always
>  Morse (US and Mexico) - tested excellent
>  Daido (Japan) - tested excellent
>  Tsubaki (Japan) - tested excellent
>  KCM (Japan) - looks very nice but was not tested
>  Rolon (India) - failed test
> 
> Note: Some of the test data was from Speed Pro, other from TRW.
> 
> 
> The Edelbrock heads probably aren't the best choice for 408 cubic inches
> and the Performer 2654? intake isn't going to make the most of the heads.
> You have to think of heads and intake combination.  It does little good
> to have a set of heads that flows 300+ CFM, if your intake only flows
> 250 CFM.  That was the case with the unported 4V dual planes we tested.
> Porting the 4V dual planes helped quite a lot but the single plane Holley
> Strip Dominator still bested them on the stroker engine, gave up no torque
> and had a smoother torque curve.
> 
> No one has offered up a set of Edelbrock (or AFD or CHI) 2V heads to test
> but I do have ported Aussie which should be pretty close to the Edelbrocks.
> If you wish to stay with 2V heads, TFS has recently introduced a 2V port
> aluminum 351C head.  If the published figures from TFS are to be believed,
> it outflows the Edelbrock and similar 2V head offerings from CHI and AFD.
> The TFS heads use larger 2.08" diameter intake valves and have a slightly
> raised exhaust port.  Also, TFS plans to introduce a matching EFI lower
> intake for use with their Windsor uppers.  Also, the exchange rate has
> recently improved for importing from Australia, so the CHI or AFD heads
> may be a better value.
> 
> > 1)  Should I stay with the Edelbrock 2665 intake or would the 7564 RPM Air
> > Gap be a better choice.  The builder thinks the Air Gap may be too tall and
> > might not fit under the engine cover (although I have a cut-out already for
> > a taller air cleaner) and that it may be more appropriate for racing than
> > street use.
> 
> The 7564 Air Gap will not fit under a stock screen but shouldn't be a problem
> if you have a screen with a cutout.  Air gap intakes or intakes (or heads) with
> the heat risers blocked will take longer to warm up in cold weather.  Even in
> milder weather, an electric choke will likely open too soon.  A manual choke
> will work better and a strong multi-strike capacitive discharge ignition will
> also help. If you want a lower profile intake that will fit under the screen
> with a drop base air cleaner and 2 1/4" tall element, the Weiand X-Celerator
> 351V-2V (7516) would be a much better choce the Performer.  In a tall intake,
> I'd probably go with one of Terry Parkers single planes though I think the
> RPM Air Gap should work okay.  I'll be testing all of these intakes and more
> on the dyno.  The 2V intake manifold line-up looks like:
> 
>  Edelbrock Performer 2V dual plane
>  Edelbrock Performer RPM Air Gap 2V
>  Holley Street Dominator 351C-2V (p/n 300-12) single plane
>  Offenhauser Dual Port 351C-2V
>  Offenhauser Port-O-Sonic 351C-2V (p/n 6122) single plane
>  Parker Funnelweb 2V high rise single plane
>  Weiand X-Celerator 351V-2V (7516), both versions
> 
> The exhaust is very important, particularly with a narrow lobe separation
> angle.  In dyno testing, we lost 50 HP with Euro GTS mufflers on a 408C and
> 50 HP wih standard Pantera mufflers on 351C.  We gained it all back with a
> pair of 3" inlet/outlet Magnaflow mufflers.
> 
> > Stroker Kit: Scat 9000 series 408 cu-in with cast crank,forged I-beam rods
> > & forged dished pistons.
> 
> Thart's the kit we used on both 408C's we've tested.  You might check
> with Alex Denysenko of MoneyMaker Racing on pricing.  Alex has very
> good prices (typically beats the big catalog places like Summits) and
> knows Fords very well.  Also, MME (Mark McKeown) has recently post his
> 2009 prices at $1199 for a 408 Cast steel kit with the SCAT 9000 series
> crank, 4340 I beam rods with 7/16 cap screws and non custom forged pistons.
> Those are the flat top piston prices.  The dished pistons are $20 more.
> 
> In case you've not seen it, I've attached a couple of posts on testing
> our first 408C.
> 
> Dan Jones
> 
> Here's a follow-up to the 408C that Dave Mclain built and dyno tested
> for local Pantera owner Glen Hartog (original post is at the bottom).
> We got a chance to finish the dyno testing this past weekend at Dave
> Mclain's shop in Cuba, Missouri. This is a 10:1 compression street
> motor that had previously made 468 HP at 5500 RPM and 486lbs/ft at 4500
> through the mufflers on 93 octane premium from the local Mobil station.
> The best pulls came with only 28 degrees total timing and a ported Ford
> low rise dual plane aluminum intake manifold. The engine makes 440 or
> more lbs/ft from 3100 to about 5600rpm but drops off after that. We
> knew the heads outflow the intake by a wide margin so we suspected the
> intake may be holding back the combo. However, the Blue Thunder high
> rise dual plane we tried was not as good as the ported Ford intake.
> Given the heavy Cleveland valves and 1.73:1 rocker ratio, we also
> suspected the OEM hydraulic lifters might not be up to the task so
> we returned to finish the dyno session with a set of Crane link bar
> hydraulic lifters (actually the Ford Motorsport part number lifters
> made by Crane) and a Holley Strip Dominator single plane intake
> manifold.
> 
> We first tried the Holley Strip Dominator intake. Equipped with a
> one inch spacer, it moved the HP peak up slightly and made around 15 HP
> more at the top than the OEM Ford intake. I forget what it made without
> the spacer but it was between the ported Ford intake with spacer and
> the Strip Dominator with spacer. Dave's got the numbers on his PC.
> Dave opined that with more RPM, the difference would likely grow and
> noted the Strip Dominator would benefit from some plenum entry work.
> The torque curve with the Strip Dominator was smoother, likely due to
> the Boss dual plane going into and out of tune. I also brought along
> an Edelbrock Torker and an Edelbrock A331 (raised port version of the
> Torker that matches A3 Ford Motorsport high port heads). It looked
> like the A331 wouldn't seal at the bottom of the port without milling
> it to drop it down, so we passed on testing it. Though it doesn't have
> much of a reputation on stock displacement 351C's, the Torker did pretty
> well. I forget the exact numbers but it was within a few HP of the
> Strip Dominator. Apparently it likes the extra cubes.
> 
> In the old (October 1993) Super Ford Article "Planes of Power",
> the Strip Donminator made 498 HP at 6250 RPM. The Torker was down
> 18 HP at 480 HP at 6750 RPM. That engine was a 13.7:1 compression
> ratio, 377 cube offset ground 351C crank, stroker with a Madden solid
> roller cam of 264/270 degrees duration @ 0.050" lift and 0.723 inch
> lift. Not sure what the lobe centers were but springs were 210 lbs
> on the seat and 510 lbs open. Given the much larger cam and higher
> compression ratio, that engine should have performed much better.
> Glen's 10:1 compression ratio hydraulic roller cam motor made
> substantially more torque (50+ ft-lbs) and a bit less HP at a lower
> RPM. Not a bad trade off for a pump gas motor expected to live a
> long trouble free life on the street.
> 
> We didn't re-baseline the engine with the dual plane at the start,
> so we slapped the ported Ford intake back on. As mentioned above,
> it was down around 15 HP to the Strip Dominator but the overall
> numbers were also down relative to the first day of testing, even
> though we had corrected for atmospheric conditions.
> 
> We next tried the Crane lifters. They are dimensionally identical
> to the Ford lifters so can be swapped without a pushrod change. Dave
> noted the custom length intake and exhaust pushrods on this engine are
> slightly different in length. During reassembly it was noticed that some
> of the intake keepers showed signs of contact at lifter collapse so the
> intake rocker arms were clearanced. Once everything was buttoned back up,
> the Crane lifters were tested and showed essentially no difference. At
> this point, we suspect the cam has too little duration to make peak power
> at the desired 6000 RPM, though Dave mentioned increasing the intake valve
> spring pressure would be worth a (future) test. The cam specs are:
> 
> Crane Cams grind number (custom): HR-232/352-2S-8
> Intake 232 deg duration @ 0.050" tappet lift
> 294 deg duration @ 0.004" tappet lift.
> 0.609" lift with 1.73:1 rocker ratio
> Exhaust 236 deg duration @ 0.050" tappet lift
> 298 deg duration @ 0.004" tappet lift.
> 0.621" lift with 1.73:1 rocker ratio
> 108 degrees lobe separation, intake centerline 103 ATDC
> degreed in at 102.25 intake centerline with new chain
> (should lose about .5 to 1 degree once timing chain loosens up)
> 
> BTW, the cam is a stock base circle core though the exhaust base circle
> is a bit smaller than the intake due to the lobe profile.
> 
> Up next was a test of the Pantera headers and exhaust. We had baselined
> the engine using a borrowed set of Hooker Competition headers (probably
> part number HOK-6920HKR) with 1 3/4" diameter by 27" long primaries, 3"
> diameter by 8" long collector with 12 inch long collector extensions and
> 3" inlet/outler Magnaflow stainless steel mufflers. Glen had a set of
> Euro GTS mufflers and had purchased the matching GTS headers from the
> Pantera Performance Center. These are nicely made with a thick flange
> and ceramic coating. The GTS headers are often refered to as tri-y's
> but are, in fact, 4-into-1 headers with short tri-y collectors. Like
> most under-car Pantera headers, the primaries are very short. The
> collector is also quite short and relatively small in diameter, though
> the primaries are large (2" diameter) and matched the port better than
> the Mustang headers. They also don't bend down at the head port exit
> like the Mustang headers. The GTS headers did pretty well. Compared
> to the Mustang long tubes, the GTS headers with a collector extension
> was a near match. Without the extension, they gave up some torque but
> were close on HP. Unfortunatey, the GTS mufflers were terrible and lost
> some 50 HP compared to the 3" inlet/outlet MagnaFlows. Though the body
> of the GTS mufflers is short the tips are very long so the overall length
> was a bit more than the much less restrictive MagnaFlows. It looks like
> the MagnaFlow muffler will fit under a Pantera and they make a version
> with 3" inlet and dual 2.5" outlets which would retain the quad tip
> Pantera look. Given that the diameter of GTS collector outlet (looked
> like 2 1/4" or 2 1/2" ID, I forget to measure it) is much less than the
> 3" pipes we used, it's possible a set of 2 1/2" pipes might not lose
> any power compared to the 3" pipes. Something to test on a future dyno
> session, perhaps. Glen likes the look of the GTS mufflers and plans on
> gutting them to try gain back some of the lost power.
> 
> Finally, we tested an out-of-the-box Holley 750 double pumper. Unlike
> the vacuum secondary 750, the 750 DP uses down leg boosters (the vacuum
> secondary version uses straight leg boosters). We tried jetting it both
> leaner and richer but the original jetting (71 primary jets, 80 secondary
> jet with power valve on primary side only. BTW, the carb has the HP type
> reinforced metering blocks) made the most power. It was down 10 or 11 HP
> at the peak compared to the 950HP dyno carb, which is acceptable. The
> carbs were tested without the aid of a bellmouth, K&N stub stack or air
> cleaner. I had brought along a freebie 850 with annular boosters that
> was in unknown condition. We tossed it on for a quick test but it really
> needs a rebuild kit.
> 
> We forgot to check the Crane steel distributor gear for wear but Dave
> can do that before Glen picks up the engine.
> 
> Dan Jones
> 
> 
> **********************************************************************
> Original post:
> 
> I recently spent some time on the dyno at Dave McClain's shop in Cuba,
> Missouri with a friend's 408 cube Cleveland stroker. Spec's on the
> engine are:
> 
> 4.030" bore
> SCAT 4" cast crank
> 6" SCAT rods with SBC pin dimensions
> dished forged pistons
> approximately 10:1 compression
> 4V closed chamber heads milled/drilled for screw in studs and guideplates
> Mid-Lift 1.73:1 roller rockers
> springs with 140 lbs seat pressure 320 open (approx)
> Ford over-the-counter aluminum dual plane (Boss 351C with Holley carb
> pattern)
> Boss 351 cast aluminum valve covers with screw-in Ford rubber grommets
> and push-in K&N breather
> Hooker Competition headers, 1 3/4" diameter by 27" long primaries,
> 3" diameter by 8" long collector (probably part number HOK-6920HKR)
> 12 inch long collector extensions and 3" inlet/outler Magnaflow mufflers
> Mallory Unilite distributor with mechanical advance only
> Boss 351C valve covers
> Dave's dyno carb (Competition Carburetion 950HP carburetor, 4 corner
> idle, no PCV port, did not use the dyno bellmouth)
> Crane Cams grind number (custom): HR-232/352-2S-8
> Intake 232 deg duration @ 0.050" tappet lift
> 294 deg duration @ 0.004" tappet lift.
> 0.609" lift with 1.73:1 rocker ratio
> Exhaust 236 deg duration @ 0.050" tappet lift
> 298 deg duration @ 0.004" tappet lift.
> 0.621" lift with 1.73:1 rocker ratio
> 108 degrees lobe separation, intake centerline 103 ATDC
> degreed in at 102.25 intake centerline with new chain
> (should lose about .5 to 1 degree once timing chain loosens up)
> Crane steel distributor gear (0.531 inch ID to match Mallory distributor)
> OEM Ford 5.0L hydraulic roller lifters and spider arrangement
> 
> The engine is destined for Glen's Pantera and he wanted to stick with
> the Ford dual plane intake so he could retain the stock engine screen.
> Knowing the Ford intake would be a limiting factor, Dave worked on the
> poorer flowing runners to bring them closer to the better ones.
> Surprisingly, the worst runners were not the lower plane runners but
> the upper runners which "look" better. The divider was cut down and
> the plenum entry blended back to help the worst runners. Two 4 hole
> spacers and one open spacer was tried. Spacer height was limited to
> 1" since that's all that will fit under the stock Pantera engine
> screen with Ford intake. The open spacer worked best but all peaked
> right around 5500 RPM.
> 
> The heads are closed chamber 4V heads with some short side radius work,
> a good valve job and stainless valves with 30 degree back cuts on intake
> side only. Here's what they pulled on the flow bench:
> 
> 351C-4V
> lift int exh int int
> #1 #1 #2 #3
> .050 33.6 27.1 32.7 31.1
> .100 64.7 55.9 64.6 64.1
> .200 123.0 100.1 129.8 134.5
> .300 188.5 138.9 195.1 200.2
> .400 246.4 166.4 251.7 253.3
> .500 294.5 182.7 296.5 294.6
> .600 322.1 186.5 322.5 322.0
> .700 333.3 185.2 338.9 330.2
> 
> Flowed at 10" and converted to 28", some porting (shortside radius work),
> 2.19"/1.71" diameter valves, no intake manifold or exhaust pipe. Intake
> port area is 3.25 sq. in. Exhaust is 3.14 sq. in. Dave's got the data
> for the rest of the ports but this all I could pull off the screen dumps.
> Dave said the shortside radius was everything on the 4V heads. He also
> opined the 2V short side was worse and would likely respond to similar
> modifications.
> 
> Flow data for head with dual plane Ford intake and 780 Holley carb body:
> 
> 351C-4V
> lift int int int int int
> port port port port port
> #1 #2 #3 #4 #5
> .200 124.0 127.4 133.0 128.9 126.4
> .400 217.9 228.8 228.6 231.7 228.2
> .600 258.9 270.5 271.7 282.4 271.9
> .800 274.4 ----- 285.3 279.7 271.8
> 
> Running through the mufflers, on Mobil 93 octane premium, the best pulls
> came with 28 degrees timing, the reworked Ford aluminum intake with a 1
> inch open spacer. Corrected numbers are 468 horsepower at 5500rpm and
> 486lbs/ft at 4500. It was a cool day and the air density ratio was very
> good, 98.17% for a 1.0238 correction factor. Air temp was 56 Degrees F,
> humidity 36% and abs baro 29.26 in Hg. Very good conditions for the
> 1100ft altitude. Dave was an EMC contestant and said his dyno is known
> to be about 4% conservative when compared to other setups. Our dyno pulls
> were from 3000 to 6000 RPM and the engine makes 440 or more lbs/ft from
> 3100 to about 5600rpm. After that, the engine drops off. The intake
> and the OEM Ford hydraulic roller lifters are the possible limiting factors
> in this build so we plan to try the FRPP/Crane link bar lifters and a Holley
> Strip Dominator intake manifold to see if wee can pull another 500 RPM or
> so. Hoping to make 500 HP through the mufflers. Once we've satisfied our
> curiosity, we'll try a 750DP and GTS Pantera headers and mufflers. Kirk
> Evans did some header testing a while back and found the GTS headers were
> pretty decent (compared to the other Pantera headers tested) but the
> mufflers were pretty bad. We'll run the tests with and without mufflers.
> Also, Dave thinks we'll only lose about 10 HP with the 750DP versus the
> dyno carb. Interestingly, he didn't bother to jet the dyno carb on the
> dyno, claiming his previous experience with that carb was that jetting only
> made a slight difference in power.
> 
> We also tested a Blue Thunder high rise intake but it actually made less
> power than the modified Ford intake. The Blue Thunder made 437 horsepower
> and 463 ft-lbs torque, at 5500 and 3900rpm respectively. Adding a 1" open
> spacer to the Blue Thunder helped the torque about 6 HP but horsepower
> stayed the same. It would be interesting to see what Dave could do with
> the Blue Thunder but we're going to try a Holley Strip Dominator single
> plane, instead. The heads alone flow 322 CFM at 0.600" lift but when you
> add the ported dual plane intake, spacer, and carb body the flow drops
> into 270 to 280 CFM range. Dave used a neat trick for the manifold testing.
> He used hardware store weather stripping instead of RTV or cork gaskets.
> Cheap, easy and lasts long enough for the dyno pulls.
> 
> Earlier I had taken some A/B measurements on several intakes:
> 
> A B
> Holley Strip Dominator 4 5/16 5 3/8
> Blue Thunder 4 7/16 5 3/8
> Ford aluminum dual plane 3 1/4 4 3/8
> Weiand Xcelerator 2V 4 3/16 5 1/8
> 
> I know for a fact the Weiand Xcelerator 2V will clear the stock Pantera
> screen with a 2 1/4" tall 14" diameter K&N element but there isn't a lot
> of room beyond that. A slightly smaller diameter air cleaner (13") should
> clear the decklid and allow a bit more space. At worst, Glen will have to
> either mill the spacer or the intake 1/4" or try a different style air
> cleaner. If he's so inclined, a taller engine screen (or spacers under
> the stock screen) can be installed.
> 
> Dave mentioned the SCAT cast crank had a Cleveland snout and did not
> require the Ford Motorsport snout spacer. If you call SCAT and ask,
> they'll tell you the snout spacer is needed. Note that the SCAT forged
> cranks may still need the snout spacer. My 4340 forged steel SCAT crank
> did need it but that crank was made a year or so ago. I don't know if
> they have separate FMS and Cleveland crank part numbers now or not for
> the forged cranks. 6" Scat I beam rod with SBC pin dimensions were used
> and the rods and pistons were light enough quite a bit of material had
> to be removed from the counterweights on the SCAT 4 inch stroke cranks
> to use the 28.2oz balance factor. It would take some heavy metal to
> make it internally balanced. Everything ends up pretty light:
> 
> Piston 390 grams(with ring support)
> Locks 4 grams
> Rings 41 grams
> Pin 117 grams
> Rod Big End 437
> Rod Small End 173
> Bearing 37
> Oil 3
> Total: 1676 gram bob weight for a 50% balance factor.
> 
> On the initial fire up, we heard some noise. I suspected a roller
> rocker was hitting the Boss valve cover baffle since I've had that
> happen before. However, Dave said he had checked that and the baffle
> had been clearanced. When we removed the valve cover, there were no
> marks on the rockers so that wasn't the source. Also, the sound appeared
> to be coming from multiple locations. After wondering if it was just
> start up slap from the cold forged pistons, Dave bumped the engine over
> with the starter while I watched for valve train interference and
> noticed that some of pushrods were just brushing the guide plates.
> Dave made the guide plate slots deeper and that took care of the
> noise. Glen thought catching was worth the dyno cost. It's one of
> those things easy to catch on the dyno (and hard to verify during mock
> since the lifters aren't pumped up) but would be a pain to catch and
> fix in the car. Required intake and exhaust pushrods are different
> lengths, BTW. That's likely due to the different intake and exhaust
> lobes.
> 
> I was surprised the Hooker Competition headers were only 1 3/4" primaries.
> 4V headers tend to be 1 7/8" since that covers the exhaust port better.
> The Hooker Super Comps are 2" but that's too large for this engine.
> Some 351C headers make a sharp down turn right at the flange to clear
> the narrow Mustang shock towers but the Hookers came out a few inches
> before turning down. Pantera headers come straight out but the primaries
> are very short and the collectors very short and small in diameter (2 1/4"
> outlet). Glen is buying a set of GTS Pantera headers which have 2"
> primaries feeding into a tri-y type collector of 2 1/4" diamter outlet.
> It will be interesting to see how big a hit we take on those relative to
> the Hooker headers.
> 
> A friend has run both the OEM Ford lifters and the Ford Motorsport
> M-6500-S58 retro-fit hydraulic roller lifters (made by Crane and
> sold by them under part number 36532-16 but the FMS part number is
> $30 cheaper through Summit Racing) and verified the lifters are
> dimensionally identical. The pushrod cup is in the same location and
> the plunger travel is the same so we can use the same pushrods. Marc
> mentioned they set the pre-load a full turn, rather than the 1/2 turn
> we were using. The full turn includes the setting of the locks (from
> zero lash to locked in place). Marc also mentioned that is what Crane
> recommends.
> 
> Since Glen is going to use the left-over stock parts to build a back-up
> engine, he's going to buy a set of the Ford/Crane link bar lifters and
> we can swap the OEM lifters to the back-up engine. With the Strip
> Dominator and the Crane lifters, we should see if the stock lifters
> are a limiting factor.
> 
> I've got all the flow data for the heads and intake so I'll run this
> through Dynomation when I can spare the time and see how well it predicts
> the trends.
> 
> Dan Jones