Just picked up a 1994 gmc sierra z71 4x4 with a knocking engine. Prev. owner got the local napa to do the machine work,had everything rebuilt and assembled and he then put it in truck. Upon start up,he says he thought it had a knock,but since he knew nothing about engines,he just assumed it was ok. Fast forward 12k miles and I end up with truck,that knocks,but only does it at start up,then after its warm only at idle. Its definitely in the bottom end. Now here is where I need yall to help me. I want to build a 383 for this truck, but dont know if the stock fuel system is enough, or if the computer will compensate. Ive never had any experience with non carb engines. By the way,the truck starts great,but after driving a while and then shut it off, it seems like its loading up extremely bad upon restart,and then you have to crank on it several seconds before it will start. So should I just scrap the tbi and go with a carb ? Sorry for the book, but I needed to try to explain my problems. Thanks in advance.

Just picked up a 1994 gmc sierra z71 4x4 with a knocking engine. Prev. owner got the local napa to do the machine work,had everything rebuilt and assembled and he then put it in truck. Upon start up,he says he thought it had a knock,but since he knew nothing about engines,he just assumed it was ok. Fast forward 12k miles and I end up with truck,that knocks,but only does it at start up,then after its warm only at idle. Its definitely in the bottom end. Now here is where I need yall to help me. I want to build a 383 for this truck, but dont know if the stock fuel system is enough, or if the computer will compensate. Ive never had any experience with non carb engines. By the way,the truck starts great,but after driving a while and then shut it off, it seems like its loading up extremely bad upon restart,and then you have to crank on it several seconds before it will start. So should I just scrap the tbi and go with a carb ? Sorry for the book, but I needed to try to explain my problems. Thanks in advance.

What you want the motor to do? Keep the FI. Trust me

Keep the cam mild (stockish) and it'll be fine. You may have to bump the fuel press a bit...maybe. These things ran a bit lean from the factory. A few (here on the board) have slid stock 400's under the TBI components.....with good results (low end TQ).

As noted above....what do you want the motor to do. You'll mess up things going above mild.

As noted above....what do you want the motor to do. You'll mess up things going above mild.[/QUOTE]

I would like it to be around 300 hp. Is that reasonable for this truck as being a daily driver ? I want it for farm work,i.e. pullin trailers and such. More concerned with the torque rather than hp,but who dont want more hp ?

Bump

By 300 hp do you mean at the crank or at the wheel? Both very possible with the tbi. Carb would be the easiest to do except for that your 94's computer controls the trans also (assuming it is an auto). But to get the best performance out of a 383 or even just swaping cams you would need to have the computer tuned. Getting the fuel system up to par with a 383 would not be too much trouble.

I would like close to 300 hp at the wheels. It is an auto trans.

I would like close to 300 hp at the wheels. It is an auto trans.

you will very likely not see 300 hp at the wheels. at the flywheel, easily, but at the wheels, very difficult to do with a small block using tbi.

you will very likely not see 300 hp at the wheels. at the flywheel, easily, but at the wheels, very difficult to do with a small block using tbi.

Should I just scrap the tbi in favor of a carb, or is there a better option to deal with the computer ? This is my first time dealing with this tbi crap,and im lost.

I'm gonna be looking at doing this soon also. I have a 94 myself. I wouldn't get rid of the TBI for a carb. You won't be as happy IMO

Not sure what these motors came with stock but mine ran good bone stock pulling a trailer. Now with 35's and stock gears it's kinda doggy. I was gonna suggest regearing maybe but not sure how hard that is on these trucks in the front