port and polish question

[Pimped Am GT]

hey whatsup guys i have a very close friend to the family that sais he can do a port and polish on my car and i was wondering how much of a power boost i can see on my 94 3.1l grand am gt and what exactly it does, and if it uses more gas

thanks, jordan

[roksoc]

depends what exactly he is porting and polishing.

[Pimped Am GT]

i think he said the head

[voyager]

i don't see where he said the head..

the head, yeah, it will use more gas. the manifolds, no, they won't use more gas. basically what you're doing is widening and smoothing the ports so more air can flow faster. of course, you'll be likely yo leadfoot it more often with motor work done, which will use more gas, but it won't be the mod's fault. you should be able to get slightly better hwy mpg with this done. slightly worse city maybe. depends on your driving style.

a top end swap with 3400 ( or 2000+ 3100 ) parts would be cheaper and more beneficial in my opinion than p&p on the 3100. you'll never port them as wide as the redesigned 3400 manifolds.

[Pimped Am GT]

yeah but my friend is doing it for me next to nothin, and i dont wanna swap the engine in my car, ill talk to him more about it, he seems to think he can probally get me about 50 or 60 more horses but we'll see how that turns out lol.

[Bjornboy81]

Originally posted by Pimped Am GT
yeah but my friend is doing it for me next to nothin, and i dont wanna swap the engine in my car, ill talk to him more about it, he seems to think he can probally get me about 50 or 60 more horses but we'll see how that turns out lol.
1. You won't get 50 or 60 hp...maybe 10.
2. He's not talking an engine swap. He said "top end" which means heads, and manifolds. Even if you just swap the manifolds from a 3400 to the 3100 you'll probably get better gains that with P&P yours.

[voyager]

you'll have to remove the heads and manifolds anyway to have them ported, so installing bigger ones in place of the stock ones is actually less work than having them P&P'd, and less down time.

[ChevelleSSLS6]

the 3400 heads are alumanum and if I remember right 3100 heads are cast iron. The 3400 heads also have bigger valves and I'm pretty sure will flow more stock than ported 3100 heads. It's the difference between old GM heads and Vortec heads.

[slowbird]

My friend did a Mild Port & Polish on my old 3.1L Sunbird. We added a 3 angle valve job, and milled the head ever so slightly to increase compression.

It ran a 15.3 in the 1/4mile with the Automatic. Stock times for the Auto are mid to high 16's.

If the heads are done right, and you increase the compression a bit, you can see some good gains out of it.

The restriction of Air flowing in, and Exhaust flowing out begins at the heads.