I am a new member here, I got a 1989 Chevy caprice classic wagon, it currenty has 215,000 and still running strong, but I came from chevy back in 1989 with the olds 307 vin y engine with the 4bbl carb on it and the ultra weak th 200 4R overdrive tranny in it, eventually I would like to install a olds 350 rocket engine with the 4 bolt mains and a olds th 350 tranny and get rid of the overdrive transmission I would rather put the chevy motor and tranny in it but i was told it would not be cost effective to do that, i need some input from other caprice owners out there. yes my wagon now has the computer in it but i want to have that disconnected when I swap the engine and tranny and i am going to go with fuel injection or a throttle body.

It is possible to keep the car pretty much stock and get the power you want. First of all, a direct powertrain graft from an 86 or older (prefer 85/86) will give you the chevy V8 and the 700 trans. Also take the ECM.

at least you will stay legal and not produce too much smog.

easier would be to use a 350, but find the exhaust manifolds from a 78/79 "R" motor. These will ahve the needed ports to pump in air, and the ECM will work as is, no change.

the 2004R *can* be rebuilt properly with a better drum so it wont explode, but it will always be the weak link. Id keep the 4spd tho and upgrade the rear to a 3.08 - that will improve the pep considerably., if you wanted to go slightly forward, 87 and newer caprice sedans had TBI and the 4spd - that would require engine, tranny, ecm and harness change, but you can then use a later (91) ecm and goto a 350 with no problem

If you already have a 350 Olds motor & tranny, that may be the cheapest way to go, but may put the smog police on your six, especially if you use an older engine with more "quench" area in the combustion chambers, which will increase HC and CO emissions. Sedans of the same vintage as your wagon came with a TBI 305/700R4 powertrain. If you can find a sedan that runs but is rusty or crashed, transferring everything Chevy over to the wagon may be your best bet. If you want a TBI 350, you'd be more likely to find one in a pickup. Belt drive components and exhaust manifolds may be different in the trucks. For the sake of finding compatible belts, hoses, exhaust parts, etc. it's best to duplicate the factory setup in the sedans as closely as possible.