I've been helping to get the new dyno system up and running at Gray's Automotive the last few weeks. We finally got it working well enough to fire up the first a long line of motors that are waiting for dyno tests.

This guy is a 383 with a 3.75 crank. It has Edelbrock 75cc heads, a Comp hyd roller and a 750 carb. It is a pump gas motor and we ran it on non-ethanol unleaded premium. Made 525 hp and 520 ft-lbs of torque. Not a race motor, she is all out of air at about 5800 rpm but it should be fun on the street.

Sweet!
But i have to ask about that intakemanifold,is that a Supervictor singleplane on a somewhat low rpm engine? i can see the benefit of the nice straight runners and straight approch into the ports in the cylinderheads but it sure seems alitle out of place on an engine that i thought would have made good use of a nice dualplane considering the fairly low peakhp rpm.

Is that an electronically actuated throttle? J.Rob

Yes, it is a 383 Victor intake. The customer supplied the intake. I would've put a Performer RPM on the engine but he decided to go with a Victor.

No, throttle is manual. Next upgrade will be a computer controlled water valve, at the moment the dyno still has a manual water valve.

We did upgrade to a mass air flow this time around though. At 525 hp this engine uses 700 cfm or 3000 lbs/hour of air. Also consumes 40 gph of fuel or 250 lbs/hour. So decent numbers all around.

Too bad he didn't take your suggestion of the dual plane. I bet he would have had a bigger smile on his face. Good numbers as is though.

I must be missing something or it is very small cam, seems like a 426 or so with RPM heads and a single plane would want to turn a few more RPM than that? TQ does seem good for that cubes though.

The chart says 450 inches with std port heads will have a torque peak at 4500 rpm which is basically what this engine does. With good cam, headers and intake the hp peak can be 1500 rpm higher than torque peak which is roughly where this engine is at.

Only thing I'd change on the engine is the intake. A Performer RPM would add a bunch of torque down low and probably wouldn't give up any power at the top.

Nice. I'm curious about the cam (what cam), and the static and dynamic compression ratios.

Thanks.

I just recently built a 383 stroker prettysimilar but with 4.25" stroke and a hydraulic flat tppet & RPM intake + 770 street avenger carb. Headers were TTI 1 3/4" primary and 3" exhaust withmufflers. It IS a nice street engine, made 550 ft-lb already at 2500 rpm, peak was 617 ft-lb at 3900, 500 hp was reaiy at 4500 and peak was 518 between 4800 and 5100.

Andy, 4.25 x 3.75 is a 426, 4.28 x 3.75 is a 432. Did you slip in a little extra stroke? this is going off your 450 cubic inch engine comment.

Jyrki, that extra half inch of stroke really made a difference. It's going to be hard to keep tires on that thing.

R.

Want to hear about the SUPER VICTOR ?
It makes suer numbers et me tell you....

A fellow racer here just did a refresh on his 416.

He raised compression 1 point to 11.8
The same old ported large port commando heads
flat tappet to solid roller cam
Going from a M1 intake to a Super Victor fully ported

Old numbers: 545 hp 543 lbs tq

New numbers: 637 hp 593 lbs tq

pretty impressive !! but personally, I don't give much of his old cast crank on the track ! lolll

Dan

Andy.. I assume you spin/start the engine using
the dyno itself... and dont need a starter and bell
housing

Correct, the starter spins the rear flywheel which is part of the dyno. We used to use a small coupler to connect the driveshaft to the crankshaft but the dyno mfg told us that using a flywheel on the engine would work better. The extra 50 lbs of rotating inertia seems to smooth things out so now we use a flywheel on the engine even though it isn't really needed.

The original method of mounting the engine to the dyno was to use a bellhousing but that is a complicated process plus you need a bunch of old bellhousings. So we scrapped that idea and I built the ring mount in the picture.

Nice engine, Andy. I agree, the performer RPM sounds like the ticket on this combo, but who are you to argue with a paying customer! I bet the Holley SD would have done well too.

I think this engine is 0.060 over so it is a 438. I'm not positive, it isn't my engine and I didn't build it. I just showed up for the dyno test to help get the new dyno system up and running.

This engine shop has a number of Mopar engines in process. Always nice to see that guys are building big blocks.

Yeah, a Performer RPM witha one inch open spacer would probably make more torque everywhere and equal HP at the top of the curve. But it is hard enough to convince customers to spend the $500 for dyno testing. Trying to talk them into buying a stack of parts and paying for the extra time to test them all is basically impossible. Very few people have a budget for parts testing.

Had another Mopar big block on the dyno today. This one is a 440 with a 4.25 stroke. Street engine with 9:1 compression, 906 heads, super small hyd flat tappet cam (240 duration), Performer RPM intake and a 800 cfm Edelbrock carb. It made 580 ft-lbs of torque at 4300 rpm and 500 hp at 5000 rpm. Power dropped pretty quickly after 5000 rpm with the small cam and stock heads but she had plenty of torque down low. It should move a big heavy car around town just fine.