You didn't say what class you would be running in.
Different sanctioning bodies have different rules.
Engine make must be same as car make - not necessarily of the same year. That would exclude a Jimmy unless you are running a GMC pick up truck. Factory only cylinder head. That would exclude both the hybrid V8 head and any non GM made head even if it looked like the original. There is a lot to think about for sure. Even if you would be running an open competition class where you can build the motor any way as long as it doesn't exceed xxx cubic inches you will be at a financial disadvantage. Almost any Village Idiot on a budget can get 400 hp out of a SBC V8.
Everyone here who has actually built a hi-po Inline will tell you that to get 400 hp out of a 292 you will spend quite a bit more than the Village Idiot did on his 350 V8. Here is a fact: 3 years ago I built up a very strong 250 Inline street engine. I spent more money just on the head work and valve gear than it cost me to build up a potent 327 V8 from top to bottom.
No one is trying to talk you out of your ideas. We just wnat to make sure you go in with both eyes wide open. And if you do build it I hope you do kick some serious V tails.
