How are the door jambs, I know they rust out on gen 2 camero's but, i'm not shure about the Firebirds. www.classicindustries.com, you'll find the parts you need. Rip out the 231 and swap it out with a 455 Pontiac, you may need to change the motor mounts but, that's no big deal, replace the cam, intake and carb. Try to get a good dual plane intake, a crane cam or comp cam and, if you have 542.00 to spend on a carb get a Predator ( available from JEGS ) or, if you don't want to spend that much on a carb, a simple 650-750 Holley is fine, double pumper is a good Holley.