Hello!

I have an 89 gmc jimmy with a TBI 5.7L which is in need of a rebuild. It's a 5000lbs daily driver that I plan on using for some occassional towing and offroad duty. I am currently trying to pick my replacement parts for the rebuild - I don't have a huge budget - but I would like to get more juice out of the motor at minimal expense of gas mileage and preferably staying on 87 octane. The problem I am having is that I don't know what kind of modifications I can make without causing the stock computer from throwing errors all over the place.

I would like to upgrade the cam, and possibly upgrade to vortec heads/intake $$$ permitting.

Any comments/recommendations?
... I'm a bit of a newbie, so please be nice

Thanks!

 

Pull up Northern Auto Parts on the web, they have rebuild kits for every engine. It comes with cam, pistons, bearings, and gaskets I believe. Adding a bigger cam won't throw a code, you just might need some computer tuning to get the most out of it. I would recomend headers, full exhaust, ult. tbi mods, afpr. Comp makes some good towing cams, a buddy of mine had one in his 86 S10 w/ 350 TPI along with a JET 6 Pack chip. It put down monstarious power and ran great without much extra tuning.

 

Then I wouldn't suggest modifying it at all.

 

You shouldnt run into huge problems doing all that. In a 305 I put in a 270* cam, World Products heads and full exhaust setup. Most people would recommend a VAFPR with any modifications but I didn't bother with one. The car ran great; the only real downside was I received poorer gas mileage.