The Olds 4.3l6 is not a bad enigne. However, why are you putting a SBC in a Cutlass? Comeon man, get origional a little here. 403, 350 Oldsmobie, 330, 425/455 will all bolt in. However, if you have your heart set on it, you can do it(Sigh). Use the brackets from the 350 as the Olds brackets will not bolt on. you need a Chevy t-350. Dnt try a 400, their too heavy. I reccomend a 700R4 for your chevy due to gas prices. Trust me, OD is a must. You will have problems clearing with the factory Chevy exhaust manifolds. Get a set of headers, bend them inwards then back out to meet your exhaust, wrap the pipes to prevent body damage and youll be good. Your PS pump will work for your SBC, so just set it aside untill its time to hook it back on. You will probably need to pully from a chevy PS pump, but thats easy to come by. I think thats it, and if you need help with a SBO swap, drop another line.