Headers tube diameter.

Moper I was trying to make the point that Jax did not need to make a custom set of headers but if he wanted my thoughts on what to buy and where to shop. Imo
I think some off shelf headers would be fine.
If I read the second part of you post correctly you are saying on average street/strip engine build bigger is better and I dont agree unless it is on a supercharged engine. On a average engine with a broad power band going to big header can have a negative effect. he needs to pick a set of off the shelf headers that fit his cam and heads.