Ported upper plenum
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From: kissimmee fl
Car: 88 iroc-z z-28
Engine: 383
Transmission: th400
Axle/Gears: 3.42
Ported upper plenum
When i do this, how much hp would I roughly gain. If I were to buy a 52mm tb would that be used to its full potential? and lastly would i gain anything even with the rest of the stock intake parts? They wont be soon im thinking of siamesing my lower intake while im changin some injectors
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From: MS
Car: 87 IROC
Engine: 5.7 TPI
Transmission: 700R4
Axle/Gears: 3.27
Re: Ported upper plenum
youd gain some but would get max if the whole air intake was ported out. meaning from air box to heads. do a search theres tons of info on it out there. also unless your looking for ungodly HP a stock TB is fine.
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From: Cincinatti OH
Car: 1991 L03 700r4 RS
Engine: 1987 WS6 Trans AM Lb2
Transmission: Th350 red neck Performance 3k stall
Axle/Gears: 95 Mustang 8.8 built with 3.73s
Re: Ported upper plenum
PORT THE BASE. I added alot of power porting out the base.
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Joined: Aug 2005
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From: California, Sacrameto
Car: 88 gta
Engine: 350 tpi
Transmission: 700r4
Re: Ported upper plenum
Didn’t seem to make it breath much better up top but oh my god, it completely changed response off idle. Nice and crisp now. And seems like I got 100-150more rpm. Auto tyranny seems to pull nice and even till factory shift points, softens up at 4600, used to soften at 4450-4500. Not bad for free, gaskets were new and soft so I didn’t even need to replace them.
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