Ok I'll start off by saying I'm totally new to the hot rod scene and old carbureted engines. I picked up a project 1966 Chevy c10 with a 454 in it. Now while I am redoing the body work etc.. I pulled the engine out as I think the main rear seal is leaking and I wanted to clean and repaint the engine anyway. Anyhow I was looking to possibly add some life to this engine. I was hoping you guys could give me a quick rundown of what I would need to achieve around 400hp. I'll give you whatever info I have now to help you out. And if there is any info you need on something please just let me know and I'll try and find it. Here is what I know so far:
Block #TO305TRW with a casting #3999889
Heads: 336781
Transmission is a TH400
Has longtube headers..but not sure which company.
Also currently has a q-jet carburetor.

That's what I know for now. I honestly have no clue if anything has ever been done to this engine whatsoever. I'm not sure if there is anyway I can identify the valves if I pull the heads off. All of these reasons brought me here for your expertise. So if you guys could maybe give me a list of what would need to be done with part numbers in order to achieve 400hp I would really appreciate it. Such as what cam and valves I might need etc. The truck will only see street cruising and not the strip. But I would like it to have some good get up and go with the classic rumble these big old engines have.
Thanks