[DeTomaso] Comments about engine build welcome

Doug Braun doug at silicondesigns.com
Tue Jan 13 11:30:21 EST 2009


Dan,

You do a great service to this forum!  After reading your post I came away
with a few questions:

Where did MME post their SCAT prices?  I can't find it on their website
www.mmeracing.com.

Would Chris' MindTrain headers fit CHI or AFD heads or are these heads the
high exhaust port type that require different headers?  And wouldn't CHI-3V
heads be a better choice for his 408 than CHI-2V?  Doesn't the added
displacement beg for the higher flow heads?

What do you consider an efficient enough exhaust in order for the LSA to be
as low as 104 for a 408 stroker?  Would a MindTrain system qualify?

Doug

-----Original Message-----
From: detomaso-bounces at realbig.com
[mailto:detomaso-bounces at realbig.com]On Behalf Of Daniel C Jones
Sent: Saturday, January 10, 2009 3:46 PM
To: Christopher Kimball
Cc: Pantera List Serve
Subject: Re: [DeTomaso] Comments about engine build welcome


> 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
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