i have a 3rd gen trans am with a 350sb
the swap is fairly easy, just get shorty style headers or they wont fit and you have to relocate frame, theres one other style, cant remember the name.
you could do it for $3,000 aside from the car fairly easily
just plan everything out good and dont build certain parts of the motor better than other cause the weakest link will always break. the weakest link for my first build was my stock rods from a 350 4 bolt
find the right small block, try to find ones thats orange and non tampered with, hopefully it will be stock bore, you can get one with smogger heads down to the pan for about $100-300 from the right guy
but like fmx said
3rd gens mostly improve on suspension, they are really loose, the swap, if you remove your A/C and heater core, will lift up the front about 2-3" just from weight on stock suspension, which makes it look funny, and ride funny.

this is my 350 on its current build, bored 0.06 over all forged internals, 488 lift cam, hooked up to a t400 w/ trans brake
3rd motor to go in this car, havent even gotten to the suspension work yet but i have all the parts in my shed waiting for the day
basically everything from the stock 305 to the 350 are the same, if you want serpentine, you can keep serpentive, i dont suggest it, but you can
the tranny should bolt right up to a 350 no problem with the right bell housing ( the one that comes on it should be the right one )
i really cant think of anything i had alot of trouble with besides getting the headers to fit the first time.
its really a simple swap just take the motor out and drop the new one in
This post was edited by t9x on Apr 17 2015 07:19am