I have an 82 olds cutlass supreme, and I really wanna put a 455 in there, and I was wondering if this is possible,and if so how hard would it be, and what other things anyone would suggest to do, such as transmissions and stuff. So any help you could give me would be really helpful.

 

Are you staring with a 307? If so it's pretty much plug and play. If you want to run headers be aware that you may need to modify the lower control arms a bit, but it's been a while since I looked for G body BBO headers.
A better option would be to get some W/Z exhaust manifolds and have an exhaust fabbed up.
The 307 brackets, motor mounts, water pump and wiring will all work, but I would suggest trying to find a harness from a 78-79 260 powered cutlass because they did not have the computer and that would make wiring up the car much easier.
Also be aware that the trans in the car be it a TH200C or a Th 200 4R will not hold up to even a stock 455 for long.

 

I have the V6, I believe it's a 231, in there now. How much does that change this whole process?

 

The wiring harness still applies, but you'll need to get some frame mounts from either a 307 or 260 car (depending on the year) and find a complete set of pulleys from a car and use the water pump and power steering pump from that car. The only thing you'll have to remember is the longer belt for the Alternator.

 

Alright, thanks for you're help.
What Transmission would you suggest?

 

Would workout just fine, I have an 81' currently in rebuild, i'll list all the particular's in a day or so, gotta be honest, I bought the car several years ago built, then it broke, but boy I tell ya is it fun to drive. Had 2 valves break and a piston crack and some minor damage to cylinder wall, so gonna have it bored .30 over and upgrade several area's, ttyl for sure