z2877

I have a 96 z28. Ive recently replaced the opti, plugs, wires, egr valve. I have a new 02 sensor I need to put on bank 1 sensor 1. I put on new cats. I was told by the previous owner that it has a new fuel pump. When I go to start it, I have to prime the pump about three times to get enough pressure to fire, the it seems to idle ok, it will rev in park or neutral but when I put it in gear it hesitates, I get a multiple misfire code, lean on both banks, and my old plugs were fouled. also Ive got some white smoke coming from the exhaust (sometimes) I really hope I dont have a bad head gasket. Does my problem sound like a fuel pressure regulator and could that cause the smoke from the exhaust or is that another problem entirely? thanks