if its a whole engine thing then why are you using hp/cyl as the only criteria and not considering CR, cam duration/timing of said engine and so on?hoffman900 wrote: ↑Tue Aug 17, 2021 6:03 pm Well, I’ve see Calvin pull off 1 3/8” on a low VE, non-crossflow 4 banger making about 58hp/cyl
It’s a whole engine thing. What can be done in the engine is dictated by what a talented header builder can get away with, and vice versa. Nothing is done in isolation!
I'm not sure what "pull off" means but unless Calvin himself build 1-3/8", 1-1/2", 1-5/8" how would you know the 1-3/8" was truly optimum? as opposed to simply better than a "off the shelf" one that happened to be larger. I'm sure for prostock and nascar he did that but for his average customer are they really getting several sets of headers each $3k a pop?
At the end of the day Calvin is not going to make this guys headers so one needs to also factor the available skills at hand and other constraints at play.