Another 383 build
I just joined the site after searching through all the 383 builds and info
I am building my first 383 here is a list of parts. What do you guys think, and what kind of torque and horsepower can I expect?
350 block 2 bolt main 010 casting bored 30 over
ARP main studs
Scat cast crank
Moroso 23020 windage tray
Melling M55HV oil pump ARP pump stud
7 qt deep pan with pickup
Pro Comp 5.7 bushed 383 rods (clearanced)
Probe flat top forged pistons
Moroso 25050 Lifter Valley Baffle
Edelbrock performer RPM heads 64cc straight plug
1.5 ratio aluminum roller rockers
.100 chromoly push rods
gear drive (noisy)
Comp Cams hydraulic roller XR288HR-10 Lift 0.520 int./0.540 exh. Duration at 050 inch Lift 236 int./242 exh.
Edelbrock performer RPM intake
APP bolts for heads and intake
The reciprocating assembly has been balanced
As for a carb I have a Holley 0-4779c 750 double pumper, but when I talked to the Holley tech they said that it's to big and to go with a 0-4778c a 700 double pumper.
Comp has a Free dyno program for download >> http://compcams.com/camquest/default.asp
Peak horsepower 545.8 @ 6000
Peak torque 535.5 @ 5000
Not to bad, I hope those are close to real numbers
I think those numbers are real generous. I'm not sure the Edelbrock Performer RPM heads are capable of that HP out of the box. Without knowing deck heights, valve relief volume, head gasket thickness, etc., I'm thinking you may be pushing the edge for pump gas with the 64cc chamber. JMO
I agree with Holley on the carb. Maybe even a 650 DP.
I don't think the lifter valley baffle will work with roller lifters. Might want to check it out.
It can still be used, according to the instructions, it says to in large the holes so that the lifter will fit. Obviously it will no longer hold the lifter in if there is a push rod failure, but it still shields the bottom of the intake from hot oil.
So those numbers look off to you, what do you think I can expect out of this motor?
I agree, the program is pretty wildly optimistic. You might get 500 hp with all your ducks in a row tuning-wise. I feel Holley is out to lunch telling you you need a smaller carb, they just want to sell you one. 50 cfm will be unnoticable, the 750 is a good choice and I personally wouldn't go smaller, especially on a dual plane intake. IMO the gear drive is a bad choice, use a good timing chain set, my opinion is the only place for a dual idler gear drive is on someone else's motor, they are too sloppy and transfer harmonics from the crank up to the valvetrain.
I appreciate all info, I will be assembling the engine in a couple of weeks so I'm looking for any input. Has anyone here ran a similar combo? Or has anyone used any of the parts I am using, if so how did the work for you?
Anyone else feel that I should stay away from the gear drive?
I think you'll find that most, if not all, the regular contributors on this board will tell you the same thing about gear drives.
If it sounds cool to you and your buddies, go for it. But you should know that the old guys will tag you as a poser who places making noise and impressing geeks as being more important than mechanical efficiency in your motor.
Thanks for the input, I will ditch the gear drive in favor of a good timing chain. Any suggestions as to which one to use?
I will say this on the gear drives. I "thought" I would like the gear drive whine in an engine I built a couple of years ago. Well I thought wrong, I hated it so much that a month after I rebuilt the engine I pulled that POS out and put in a good chain set-up. I ended up going with a Cloyles Double roller set up......
I might use this set if I were building a more performance-oriented motor. Both sprockets are hardened and the set is hand-matched at the factory....
If I were interested in changing the cam phasing to find the sweet spot cam-crank I might use a Hex-A-Just set like this...
and a timing cover like this to allow easy access to the adjustment....
First, let me say that I've had enough feedback from several different sources including professional engine builders who flow these heads in the real world to convince me that flow figures published by head manufacturers are pretty much bogus and are inflated in order to sell heads. Since I don't have the facilities to flow each head before I enter it into the DynoSim software, I've decided to factor published head flow by .90 in an attempt to approach reality. I'll post that caveat on each DynoSim pull that I do from now on, including this one for you.
Now, with that said, it looks like you'll need more head to reach 500/500. On a brighter note, I don't know if you chose the cam for this combo, but if you did, kudos to you. You nailed it. I couldn't find any more power with less or more cam on this DynoSim pull.
It's a shame that Edelbrock hasn't stepped up to the plate with the RPM-XT head for the small Chevy. They have it available for the 351 Ford, but not for the SBC yet. That's the head that a 383 needs.
Using 64cc heads, 6cc's in the piston crown, an 8cc gasket and zero deck, I calculated a 11.05:1 static compression ratio for your build.
THE PUBLISHED FLOW FOR THESE 60899 EDELBROCK RPM HEADS HAS BEEN FACTORED BY .90 FOR THIS DYNOSIM PULL.
RPM HP TQ
2000 145 380
2500 184 386
3000 235 411
3500 296 445
4000 355 466
4500 404 471
5000 442 464
5500 460 438
6000 448 392
Peak volumetric efficiency 99.5% @5000
Peak BMEP 185.7 @4500
1.6 rockers on both valves will only add 6 hp, so I wouldn't think it would be worth the extra stress on the valvetrain.
Just because I like doing this, I ran the numbers on the RPM-XT Ford heads and factored them by .90 as well, figuring that when Edelbrock releases the Chevy head, it will be close to the same flow as the Ford...I used the same cam as above...
RPM HP TQ
2000 144 381
2500 183 384
3000 236 414
3500 303 454
4000 369 484
4500 427 499
5000 473 497
5500 499 476
6000 506 443
6500 477 385
Peak volumetric efficiency 104.7% @5000
Peak BMEP 196.5 @4500
It's clear that your combo needs more head.
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