If someone wants to loan me a set of 2 inch chassis big block headers I’ll do the test.
As long as the chassis headers are adjustable they will beat up fenderwell headers every time. There isn’t an engine out there (with correct cam timing) that wants a primary tube that long.
In fact, IMO as the primary diameter goes up, the primary length needs to go down. That may seem counterintuitive but it’s not. In that case you are tuning primary length against primary diameter.
