[DeTomaso] Dyno Results from Another Pantera Stroker Engine

[Daniel C Jones]

More from Dave on the 438 Clevor build:

"I tried hard to make the engine as durable and maintenance free as is possible
with this sort of build and that means making compromises mostly with
the camshaft.
It's pretty mild so I don't think it'll be particularly high maintenance.  The
biggest thing is to just pull the covers from time to time and have a
look at the
valve train/lash etc.  That'll tell you a lot.  And I think that the valvetrain
will be the area of the engine that will require the most maintenance.

Since this engine is built using the Windsor design block I was able
to get a cam
ground using an Everwear core.  That's the two piece cam core with a
gear that will
allow the use of a regular cast iron distributor gear.  I used an MSD billet
distributor and just deburred the gear and adjusted the advance
mechanism to make
the curve shorter and come in more quickly.

I've used profiles from this series in jet boat applications that have
run on the
river every weekend for the last couple of years on a set of springs
without trouble.
I'd probably just check the lash a couple of times a year with
moderate use and then
plan on pulling the intake after about two years to inspect and
probably replace the
lifters.  From what I've seen with this spring they will still check
good when it's
time to freshen the heads.  On the CHI's I deliberately gave them a
wide seat even
though that probably hurts performance a little I feel that they will
stay nice longer.
These are a very smooth lobe that are easy on parts, it's most
certainly not a drag
cam.  Also the fact that it's ground on a pretty large(Ford) base
circle also softens
up the profile a little which helps."

Dan Jones

On Thu, Feb 17, 2011 at 6:38 PM, Daniel C Jones
<daniel.c.jones2 at gmail.com> wrote:
> Dave McLain built and dyno'd another Pantera engine.  This time it's a solid
> roller cammed 438 cubic inch short block with unported CHI 3V Cleveland
> aluminum heads and matching single plane intake.  It made 666 HP (yes, the
> Mark of the Beast, how appropos) at only 6300 RPM and 627 lbs-ft at 4700 RPM
> through the mufflers running on premium pump gas.  That's on a dyno that reads
> 4 to 5% low compared to the calibrated Engine Masters Competition dynos.
> 666 * 1.05 = 699 HP.  Dayum!  Details of the build:
>
> Heads are stock 225cc runner CHI 3V's.  They have PBM stainless valves with
> 30 degree back cuts on the intakes only.  2.190" diameter intake and 1.75"
> exhaust.  All that was done to the heads was to finish the seats, hone the
> guides to get the correct clearance and machine them for 0.502" diameter
> Viton seals and ID style spring locators.
>
> Cam is a solid roller ground by Steve Demos that uses Reed ULX lobes with
> durations at 0.020" of 290 degrees intake and 292 degrees exhaust.  At 0.050",
> it's 254/258 degrees.  Lobe lift is 0.400" intake and 0.405" exhaust.  With
> the Yella Terra 1.73:1 roller rockers, the zero lash lift is 0.692" intake
> and 0.700" exhaust (minus lash of 0.024" to 0.026" hot).  Intake centerline
> is 104 degrees with a 108 lobe separation.
>
> Springs are Erson E915043 with 235 lbs on the seat and 610 lbs at 0.700" lift
> on both intake and the exhaust sides.  Titanium retainers are from PBM.
>
> Carburetor is a Competition Carburetion built 950HP with 76 jets front and 88
> jets rear (no power valve in rear).  CHI 3V 4150 style single plane air gap
> intake.  Both a 1 inch open spacer and a 1 inch HVH merge spacer were tested
> and were virtually identical (open spacer made 664 HP and 630 lbs-ft torque,
> HVH made 666 HP and 627 lbs-ft).  Best power came at between 28 and 30 degrees
> total timing.
>
> Headers used on the dyno are the Mustang Hooker Super Comps we used on the
> dyno project 351C engine with 1 3/4" primaries and 3 inch diameter collectors
> that are about 6 inches long with a 12 inch extension into 3" inlet/outlet
> Magnaflow mufflers.  180 degree Pantera headers will be used in the car.
>
> A Dart SHP block with a 4.125" bore was fitted with a Scat 4.1" stroke forged
> crank for 438 cubic inches of displacement.  Rods are 6.2" in length from RPM
> and the pistons are from Diamond with a dish giving the engine approximately
> 10.5:1 compression.  Dave didn't deck the block.  Instead he bought a Cometic
> head gasket in a 0.031" compressed thickness to give the desired quench
> distance.
>
> Lifters are from Morel, pushrods are 3/8" diameter 0.080" thick wall from
> Trend.  Balancer is a Power Bond.  A stock Melling 351 Windsor oil pump
> was used though the bypass spring plug was pressed in a little deeper to
> raise the relief pressure slightly over the stock 60 PSI.  The engine has
> about 70 PSI above about 4000 RPM and it idles with about 45 PSI hot.  Dave
> set it up with moderate bearing clearances and feeds the valvetrain through
> a 0.075" restrictor.  Oil pan is an Armando Pantera road race style pan.
> Oil is 15W-50.  Filter is a 2 quart Hastings LF 426.
>
> Gaskets except for the head and intake are Felpro, stock rebuilder.
>
> Timing cover is a new aftermaket stock replacement piece.  Timing set is a PBM
> billet gear set with a Torrington thrust.  Dave retained the eccentric so an
> engine mounted fuel pump can be run.
>
> Dan Jones
>