I have a 1985 Camaro and i want to swap a Oldsmobile 455 and i don't know what exhaust to use and i do not know if it will fit. Any help would be appreciated.

 

If you must have a big block, then sell the Olds and buy a 454. Otherwise, sell the 455 and get a 350 Chevy.

 

Do you have a transmission to go with the motor? Olds/Buick/Pontiac use a different bellhousing pattern than a Chevy.
Beyond that, what you want to do is a completely custom operation including motor mounts and exhaust.
Will it fit? Of course it will. Will it be a simple drop in? Absolutely not.
Don't let me discourage you. If you want to drop an Olds 455 in a Camaro, then do it. But if you are wanting to do it because you already have the motor, you may want to re-think and possibly sell it off and get a big block Chevy(If your desire is for a big block). There is a lot of information on putting a big block Chevy in these cars.

 

I didn't detail all that because if they can't figure that much out for themselves then they sure cant figure out how to complete the sewap, and since the question was asked, the OP was hoping the swap parts already exist, which they don't.
If the idea is a non-Chevy engine, then the Pontiac is the next best 455, not the Olds. If the idea is a sporty car for the Olds, then an '84-or-so Cutlass Supreme gets the nod. '77-'79 TransAms had the Olds 403, so maybe a older Firebird is an option.

 

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