Horsepower/Torque difference between 347 and 383?
Thread Starter
Joined: Jun 2002
Posts: 669
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From: Amarillo, TX
Horsepower/Torque difference between 347 and 383? Did some reading but really couldn't find good numbers. Anyone know what the difference would be between a forged 347 and forged 383, everything else being the same?
For example: My setup with TSP 5.3L stage 2.5 heads, what kinda difference could be expected?
Thanks, James.
For example: My setup with TSP 5.3L stage 2.5 heads, what kinda difference could be expected?
Thanks, James.
If you transferred your heads, intake manifold, throttle body, cam and headders to the 383, your torque would go up by about 7% and the torque peak would occur at about 200 RPM's lower. Your peak HP might go down a few percent and the RPM of peak would be lower. That's my two cents.
Steve
Steve
Thread Starter
Joined: Jun 2002
Posts: 669
Likes: 1
From: Amarillo, TX
Originally Posted by Steve Bryant
If you transferred your heads, intake manifold, throttle body, cam and headders to the 383, your torque would go up by about 7% and the torque peak would occur at about 200 RPM's lower. Your peak HP might go down a few percent and the RPM of peak would be lower. That's my two cents.
Steve
Steve
...that seems quite low compared to what I have read. 
11 Second Club
Joined: Jun 2005
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From: Was New Orleans, but swam to Baton Rouge
Originally Posted by Dr. Jeckel
So your saying that with heads and everything else that my torque would go from around 400 to only 428 ...that seems quite low compared to what I have read.
...that seems quite low compared to what I have read. i don't know about the percentage thing.that might be the case if your heads were maxed and you couldn't keep up with more cubes but almost always nobody has their setup maxed. all the extra cubes is coming from a longer stroke.usually a decent setup makes close to it's cubes in tq at 3k so if a 346 makes 346 rwtq @3000 then a proper 383 should make 383 rwtq @3k which would be 37 more ftlbs.of course as always there is variables but a decent head like the prc 2.5 should be able to feed a 383 and make such power.
Thread Starter
Joined: Jun 2002
Posts: 669
Likes: 1
From: Amarillo, TX
https://ls1tech.com/forums/showthrea...&highlight=383
Judging by this thread I should be looking at approximately 40rwtq increase, with similar horsepower. Nice call slowtrap
Judging by this thread I should be looking at approximately 40rwtq increase, with similar horsepower. Nice call slowtrap
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Im really glad that you started this thread cuz i plan on stroking mine to 383 this time next year and i have the same heads i would just need alarger cam. So guys keep em coming woul like to hear more opinions
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