I have a 1969 gmc 1500 truck, its lowered with 275/50-17's (all the wheels are all the same) and i had this truck when i turned 15 and i had a pos 350 in it, the motor locked up. so i replaced it with a 383 stroker with a 350 turbo tranny. i love this truck to death but it runs like ****. when i got to take off it stumbles and then smooths out after you give it gas. well i had a couple guys i know helped me time it and now it runs worse than before. i think i need to hook up a vaccuum pressure guage to it and do it that way...good idea? also i need some good advice on a good rearend i want something that is and all around good rearend. im thinking a 373 or like a 355 or something. if you can help me thank you.

 

the motor im not sure on, but it is carb. i dont know the cam size but the guy i bought it from said it was the 2nd largest one you can buy for a 383, does that help any. sorry im still kinda learning but i think i need a diffrenet carb i have a 750 holley on it now but i think im going to throw a edelbrock on it

 

As for differentials, 373s are generally agreed upon to be the best power/economy combo, unless you do a LOT of highway driving.

You may not need a carb. A high-performance cam will almost always run like crap at low idle. The vacuum gauge is always a good thing for monitoring engine performance.

Then, a return to basics, check timing, firing order(make certain those wires are right) and properly adjust your choke. Try not to get too many hands under the hood, and make sure the left hand knows what the right hand is doing, and vice versa.

 

1GARY i have a question where do i hook up the vacuum pressure gauge when i time it?


and do you know where i can find some pro-star wheels for my truck that are wide in the back and skinny's in the front? i don't have a lot of money but i want a drag looking wheel rather then what i have.



oh and i don't think i told you but i really appreciate the help, i love getting on the forum (though i have a GMC ha ha) and hopefully getting smarter from all the advice.

 

The vacuum gauge usually comes with instructions and a small hardware package, but if you got a name-brand used unit, that's OK, you want to hook it up to the intake manifold. Generally there's a threaded hole with a plug or that's in use which you can connect to using a tee adapter. You may need to get the brass adapters from a car parts or hardware store.

An internet search may help with the rims, but you may have to get two complete sets of different sized rims to get the look you're seeking. Rims and tires are a very personal thing.
Be sure to keep us posted how it's coming along.