383<394 Cubic Inch Mopar Engine Build

This project is for a guy I work with. He bought a partially assembled engine to start with. I have guided him in the purchase of the remaining parts with the goal of 450 HP and gobs of torque. We're not sure what car this engine will end up in but likely a late '60s "B" body like a Charger, GTX or Road Runner. I'm pushing for a '67-'69 "A" body Barracuda - preferably a non-fast back model but it's not my $$ so I don't get much say.

Here's a shot of the like new Edelbrock TM-6 intake. Hot Rod Magazine tested 30 or so intakes on a 450hp 383 a few years ago and this intake was within a couple HP of the best as far as peak HP goes but beat almost all for making torque.

The heads for this engine are a pair of nicely done #452 castings that have been cut for larger valves. I'll remove the valves and do some port work on them. They should flow more than enough to reach 450hp.

It's easy to see where the intake port restriciton is-the pinched side is due to the pushrod location. You can't remove a ton of material from that area or you will grind through the casting. Mopar made a set of templates for porting the valve bowl areas, I'll check to see if those are still available.

Update June 2008:

I spent the afternoon messing around with Engine Analyzer Pro to see if my parts ideas will meet the expected goal. So far I'm pretty pleased. The program calculated the HP to peak at 479/5500rpm and 300 lb ft of torque just off idle rising smoothly to a peak of 506 at 4500rpm. This is with 11-1 compression, a Comp Cams XE284H hydraulic cam, 1 7/8" header with 38" long primaries, 3" collector 24" long. I personally think the HP estimates are a little optimistic but it should easily reach the 450hp goal. The 500+ lb ft of torque should make it very fun, even in a heavy car.

I tried the Comp Cams XS282S solid lifter cam and it was a REAL torquer with up to 40lb ft gains over most of the curve over the 284H cam. If this was MY engine that's what I would run but I'm not afraid of adjusting my valves once in a while. For a customer the hydraulic cam is the way to go.

I need to get these heads ported and the rest of the engine into my garage so I can see what I REALLY have to work with. I will have to tear it all down and check everything out as I have found you NEVER really know what you have unless you built it yourself!

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