I have a 87 firebird. 6 month ago I had a engine swap done with a early 70 350. I believe it was out of a 3500. It had a 650 holly, shoty headers going thru a high flow cat, then a flowmaster cat back. Edlebrook manifold and a cam with a .50 lift and accell plugs, wires and distributor. It rolls but I fell something is holding it back. I think it may be heads. It is about as fast as my 2002 but not faster, which would put it at about 350hp.

 

well what heads are on the engine now?