new 383 is slow
here's the specs:
440hp @ 6000rpm 460 lbs/ft @ 4100rpm
Duration:
Intake: 224@ .050
Exhaust: 230@ .050
Lift:
Intake: .540
Exhaust: .550
Lobe
112
4-bolt main caps and ARP main studs.
Crank: Eagle cast steel, internal balanced front and rear
Rods: Scat 4340 forged steel, 6¡n length, floating pin
Pistons: SRP Forged
Rings: Speed Pro Plasma-Moly
Bearings: Clevite Main and Rod Bearings
Lifters: Comp Cams Hydraulic Roller
Pushrods: Comp Cams High Energy
Valve Springs: Comp Cams
Rocker Arms: Comp Cams Aluminum Full-Roller 1.6 Ratio
Multi angle fully ported LT1 heads
I was seating the rings last night-- full throttle through 3rd gear then letting off and coasting back to idle-- and it felt like I'm missing about 150 horsepower.But it runs pretty good and smooth, I had to turn up the idle bc it runs rich, but its not like hesitating or backfiring or anything.
My old bolton 350 (261rwhp) felt just as fast as this new 383.
Now, I haven't gotten a tune for the 383 and I am still on my 24lb injectors and it's running pretty rich, but jeeze, it couldn't even chirp 2nd shifting at 5500
...Is the PCMforLess tune going to fix this? because if it doesn't, there will be a brand new 383 going up for sale....
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After my head/cam install, I had the same feelings you're having. Fortunately I was wrong and the car did turn out to be a bit quicker than before. Tuning can make a huge difference. Hopefully, for you it will.
Good luck.
after years of running that setup i lunched a piston. so i built my 355. stock crank, 6" rods, SRP flattops, Stage II heads, 236/242 .556/.576 112 cam, 58mm TB, longtubes, Mufflex 4" catback.... few other minor parts... also had a piggyback Accel Gen VI DFI system...
got it started and Joe Overton came over to tune it. spent about 30 minutes tuning initially setting up idle, coolant and IAC functions.... then got into spark and fuel tables. then all of a sudden a nasty backfire started... he spent another 30 minutes trying to get rid of it. no dice. we take it out for a spin and it's bucking pretty good. it's loud and felt powerful. we get it on the road and he tells me to lean on it ( I secretly FLOOR IT
) Car kinda starts to pull a bit.... I'm frowning and it's killing me inside.... Joe leans over and sees my face and says "don't worry it'll feel much better when you floor it" (which made me feel 10 times worse).... i never said that i did floor it....After we get back joe asks me if my opti routing on the wires is good and i don't have a plug wire going to the wrong hole. I tell him I'm a pro and that would never happen
A day later I check over wires again and find #2 and #4 are crossed on the opti.... take the car out and it feels like it has THREE stock LT1's.. Absolutely animalistic acceleration, no surging, just clean power.... Moral of the story: Trust Joe Overton and the buttometer is fairly accurate when it comes to knowing the diff between 308 RWHP and 422 RWHP (which my car later made NA)... Check the simple things like fuel pressure under load, crossed wires, and the phantom power killer "Burnt plug wires" which occur ALOT with new engine setups seeing as how you just routed the wires and they could have touched the headers..... little tip. start your car in the garage with no lights at nighttime. let your eyes adjust and stare into your engine bay near the headers, spark plugs and opti.... if you see sparks jumping or arcing you have a bad plug wire.... just a good tip to go by. hope this helps man and you find your lost power....
Go over your plug wires again. Mine were crossed on the initial start-up.
24's are too small but you should still have great torque. My 30's are hitting around 87 Duty Cycle with my setup (383, AFR 190s, GM847)






