i just got my new 350 hooked up and running (way out of tune at the moment), last night. but, there is smoke coming from the exhaust manifolds. i'm thinking one of two things: residue from cleaners and rust converter that i used on them several weeks ago, or leaking over-rich exhaust smoke from the flange were the manifolds meet the y-pipe. when i took the exhaust apart, before pulling the old engine, i found no gaskets there, so it seems i shouldn't need to add them now. anyone else run with just the flared pipe? it's tough to pinpoint the exact source, since it was a night, and also, the smoke is light and rises around the manifolds quickly. doesn't seem to have any adverse affect on the engine itself.