i have a 1990 gmc sierra 1/2ton stepside truck with a 5.7 350 tbi and 700r4 tranny , and i want to put a new 305 5.0 engine in my truck, the original engine is getting tired and i have a new 5.0 305 engine that i was going to put in my 90 caprice that i sold last year ,the new engine is a center bolt long block new from gm.
so what is required ,besides the basic engine/tranny swap, to make this engine work , do i need a new chip for the computer?
i know that my in take and oil pan ,valve covers intake and exaust manifold , distributor ect will fit,
so what else do i need to know before i start?

The block should just drop right in, with out much of a problem. They're both basically the same block, with different sized cylinders. As for your computer, I think the truck's old enough in which the computer won't notice the difference. Are you sure you want to go with a 305? My 84 Caprice with the 305 isnt exactly the quickest thing in the world. I guess it'd be ok if you already have it, its got enough torque, it hauls my big *ss car around :-).

The computer is the same but the chip (program) is different.

//2000CAYukon

thanks for the info , the chip is what i was thinking about as well,
plus better fuel mpg , and 305's have enough vroom for me. :smokin:

So the 350 and 305 have a different chip? The reason I ask is because I just did the opposite to my '88 Sierra - went from a 305 tbi to a 350 tbi. Should I go to a junk yard and pick up the chip off a 350?

mellowyellow598,
Take a look at http://www.tbichips.com/faq.htm

//2000CAYukon