[DeTomaso] Intakes.

[Daniel C Jones]

On Tue, Feb 23, 2010 at 10:39 AM, Larry Finch <fresnofinches at aol.com> wrote:
> Dan wrote: <<<unported iron 4V heads>>>
>
> Dan, can you clarify info on these heads?  Open or quench? Valve size?

For the 4V intake manifold tests, the heads were unported iron closed
chamber 4V heads with 2.19" diameter intake and 1.71" diameter exhaust
valves.  We've also tested CHI-3V and the Pro Comp clones.   We have
around 8 other sets of heads to test.

> For that matter, can you refresh our memories on the details of the
> block  you are using?
>
> CID, pistons, rods, lifters, etc?

The short block is a standard performance rebuild of a 351C with the
following parts:

 Ford 351C block, 0.030" over (4.03" bore), 2 bolt mains, block did not
 require a re-bore as it had low miles since last being bored and was in
 good shape (no ridge), block was decked to clean up gasket surface
 Pioneer brass freeze plug set
 TRW L2379F forged flat top pistons with dual valve reliefs
 Ford 351C forged steel connecting rods (5.78")
 Ford 351C nodular iron crankshaft (3.5" stroke)
 Powerbond SFI balancer
 Ford Motorsport double roller timing chain (French Renold chain)
 Melling M84AHV mechanical high volume oil pump
 Ford Motorsport M-6005-A351 heavy duty chrome moly oil pump driveshaft
 Ford 351C passenger car front sump 5 quart oil pan
 Weiand 8209 aluminum 351C water pump
 MSD 8480 distributor (mechanical advance, large cap)
 Crane steel distributor gear (p/n 52971-1 for 351C with .531" shaft dia.)
 Cometic head gaskets (p/n C5871-040 for a 4.1" bore 351C/351M/400)
 FRPP M-6500-S58 "Early Block Hydraulic Roller Lifter Set". These are
 Crane p/n 36532-16 link bar retrofit roller lifters but were a little
 cheaper under the Ford Racing part number.
 Trend custom length push rods (shorter to suit the taller roller lifters)
 Hastings moly rings (351C stock replacement)
 Clevite rod and main bearings (Std/Std)
 Crank treated to a light polishing
 Clearances are .0025" on rods and .0027" mains
 Fuel pump block off plate (dyno providing the fuel flow)

The engine was assembled by Dave McLain of McLain's Automotive who is also
providing the dyno services. The reusable Cometic head gaksets were provided
by Alex Denysenko of MoneyMaker Racing. The block and iron heads and intakes
were painted by fellow Pantera owner Mike McDougal. Many more people have
contributed parts or cold hard cash to this effort, so I'll have a lot
more people to
thank in the installments to follow.

The camshaft is from Reed Cams in Georgia and is a custom hydraulic roller,
specifically part number 535-TM280HR-284HR-107A, and is ground on a standard
base circle steel core. In picking the cam specs, we were after a street
performance grind that would have a horsepower peak near 6000 RPM with a
best shift point of 6500 RPM, a wide mid-range torque band and some idle
rump-rump.  We also wanted a cam that would work well with all the heads to
be tested which range from open chamber 2V iron to Ford Motorsport aluminum
high ports to CHI 3V's. We chose a hydraulic roller to avoid the lobe and
lifter wear problems associated with the low ZDDP content associated with
current automotive oils. Also, I'm a lazy street guy and setting lash on a
solid cam is a bit of a chore in a Pantera. The cam specs are:

 228/232 degrees @ 0.050" lift (280/284 @ 0.006"), 0.588"/0.588" lift,
 107 LSA, 68 degrees overlap, installed in the engine on a 104 intake
 centerline.

The 68 degrees of overlap should put us in the right ballpark for a
street performance cam in an engine of 351 cubic inches, considering
our relatively large intake valves. I picked the lobe separation angle
using David Vizard's cam selection guidelines. Theoretically, for this
combination of bore, stroke, intake valve diameter, compression ratio
and overlap, this LSA should give us the best area under the HP curve
but not necessarily the best peak HP. For our valve diameters, Vizard's
guidelines suggest very large lift of between 0.615" to 0.766", with the
caveat that lift be limited to whatever is consistent with the longevity
goals. Since our goal was a street engine, we went with a relatively
modest lift of 0.588".

Dan Jones