<div dir="ltr">That's good stuff, Dan.<div>I don't feel too bad... :-)</div><div><br></div><div>I got 544 with my stock 4V iron heads (that weren't ported) and 393ci.</div><div>I suppose I should qualify it further... Open GTS headers and EFI.</div>
<div><br></div><div>17 more cubic inches and 16 more HP for Brian.</div><div><br></div><div>Really good stuff!</div><div><br></div><div>Thanks for continuing this! I love these reports.</div><div><br></div><div>Regards,</div>
<div>Kirby</div><div><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Feb 6, 2014 at 11:22 AM, Daniel C Jones <span dir="ltr"><<a href="mailto:daniel.c.jones2@gmail.com" target="_blank">daniel.c.jones2@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">The odometer on Brian Hill's 1971 Pantera showed 60K miles but its 351<br>
Cleveland was burning some oil. The history of the engine was unknown<br>
and Brian wanted more power anyway so it was decided to build a<br>
stroker Cleveland. Dis-assembly revealed the block had already been<br>
bored 0.030" but had a few thousandths of wear so was honed to a<br>
4.040" bore. A Scat stroker kit with Probe forged dished pistons, 6"<br>
rods and a forged steel 4" stroke crank was used to provide 10:1<br>
compression and a displacement of 410 cubic inches. The distributor,<br>
carb, water pump, alternator were new and the McLeod flywheel had been<br>
recently resurfaced so those parts were re-used, along with the<br>
Pantera 10 quart oil pan.<br>
<br>
Most of the stroker Clevelands we've done have been with aluminum<br>
heads (Ford Motorsport A3 high ports, Ford Motorsport C302B high<br>
ports, Brodix BF300 high ports, CHI 3V and 4V, TFS 2V, etc.) but this<br>
one was the first in a long time that retained the 1970's era OEM cast<br>
iron 4V heads. The heads were rebuilt years ago with replaceable<br>
bronze guides and had been milled and drilled for screw-in studs and<br>
guide plates. Dave McLain machined the spring pockets for double<br>
springs, installed single groove valves, did a valve job and<br>
resurfaced the heads. They looked pretty good so no additional<br>
porting work was done. On the SuperFlow bench, they flowed:<br>
<br>
Lift Intake Exhaust<br>
Inch CFM CFM<br>
0.025 13.90 10.90<br>
0.050 33.10 26.50<br>
0.100 66.40 52.20<br>
0.200 140.20 97.90<br>
0.300 201.20 129.90<br>
0.400 251.40 152.30<br>
0.500 290.90 165.50<br>
0.600 313.90 172.70<br>
0.700 301.70 173.30<br>
0.800 303.20 174.70<br>
<br>
I used Dynomation to design the cam, starting with the simulation and<br>
dyno results of the 408C we did for Glen Hartog's Pantera. That<br>
engine also used cast iron closed chamber 4V heads but those had some<br>
short-side radius work and flowed a bit better (322 CFM @ 0.6").<br>
Compared to the dyno data from Glen's engine, the latest version of<br>
Dynomation was under-predicting the RPM of the HP peak so I biased my<br>
goal to make sure the cam would peak at 6000 RPM, providing the best<br>
average HP between 4000 and a 6500 RPM shift point. That works well<br>
for a street driven Pantera with stock gearing and still pulls strong<br>
at lower RPM. Rather than use the Bullet lobes we'd used in the past,<br>
Dave worked with Steve Demos and Mike Ingram to design a couple new<br>
hydraulic roller lobes. The lobes are based upon the Ford base<br>
circle, not the smaller Chevy base circle of the previous Bullet lobes<br>
we've used. The resulting Demos hydraulic roller cam was checked using<br>
Cam Analyzer v4.0 and proved to be very close to the requested specs:<br>
<br>
Cam # DM238HR/DM242HR, Grind 0001<br>
279.3/282.8 advertised duration<br>
239.6/242.6 degrees duration @ 0.050"<br>
159.8/162.4 degrees duration @ 0.200"<br>
0.620"/0.621" intake/exhaust lift (with 1.73:1 rocker arms)<br>
109 degrees LSA<br>
108 degres ICL<br>
<br>
Seat Timing<br>
Intake Open 28.8 BTDC<br>
Intake Close 70.5 ABDC<br>
Exhaust Close 33.8 ATDC<br>
Exhaust Open 69.7 BBDC<br>
<br>
0.050" timing<br>
Intake Open 10.8 BTDC<br>
Intake Close 48.8 ABDC<br>
Exhaust Close 11.9 ATDC<br>
Exhaust Open 50.7 BBDC<br>
<br>
PBM/Morel link bar hydraulic roller lifters were used and the roller<br>
rockers from the original engine were retained. Previously, we had<br>
tested a bunch of intake manifolds on Mike Drew's 408C with CHI 4V<br>
aluminum heads. The best of the lot were the Edelbrock Scorpion,<br>
Holley Strip Dominator and a ported Blue Thunder dual plane. The<br>
Edelbrock Scorpion is no longer in production but I found a good used<br>
one so we went with it. Looking much like an Edebrock Torker, the<br>
Scorpion is taller with a level carb pad (nice to have in the Pantera<br>
which has a level mounted engine and transaxle). Dave did a lot of<br>
work on the entry radius of the ports in Scorpion's plenum. On the<br>
dyno, best power was made with a 1" open spacer and best torque was<br>
with a 1" HVH spacer it only dropped a few horsepower and a few lbs-ft<br>
of torque without a spacer. Brian supplied a Holley 750 carburetor<br>
(p/n 80528) which I thought might be on the small side for the stroker<br>
engine but watching the manifold vacuum during the pulls showed no<br>
significant depression so it looks like it's adequate for the 6000 RPM<br>
410C. It seems snappy and idles clean. The engine liked 30 degrees<br>
for total timing. Brian will be using a stainless Wilkinson Pantera<br>
exhaust system which performed well in previous testing but the engine<br>
was tested with the following exhaust on the dyno:<br>
<br>
Hooker 351C Competition headers (part number HOK-6920HKR)<br>
1 3/4" diameter by 27" long primaries<br>
3" diameter by 8" long collector<br>
12 inch long collector extensions<br>
3" inlet/outlet Magnaflow mufflers<br>
<br>
Based upon the simulation results, I thought we'd hit 500 HP at 6000<br>
RPM but the engine really surprised us by making 560 horsepower at<br>
6050 RPM and 526 lbs-ft at 4600 RPM through the dyno exhaust. Not too<br>
shabby for a street cam and factory iron Cleveland heads. Seems the<br>
big port heads really like the extra cubes. Previous testing has<br>
shown the 4V heads also respond to a shorter exhaust rocker ratio and<br>
to exhaust port stuffers (MPG Stingers). It would have been<br>
interesting to see if we could squeeze out a few more ponies but I<br>
think Brian will be pleased with the results. He kindly offered to<br>
let me use his engine to do back-to-back testing between his iron<br>
closed chamber 4V heads and a set of my Ford Motorsport aluminum high<br>
ports (ported C302Bs) but with the very cold weather this winter<br>
Dave's running a bit behind on the dyno so that testing will have to<br>
wait. The dyno rolls outside the shop and hooks up to an external<br>
water source so it needs to be above freezing weather which the latest<br>
forecast says won't happen in the next week. We'll pick back up with<br>
testing the C302B heads on my 407 Fontana engine in the spring. FWIW,<br>
the Dynomation simulation predicts another 70 HP for my ported C302B<br>
heads and intake.<br>
<br>
Dan Jones<br>
<br>
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</blockquote></div><br></div>