Guys I can fit 2.25" TTI headers into my car easily enough.

My question is: will a 3.5"collector be enough for a 6500rpm max 572" N/A Hemi ? Engine makes 845HP/770TQ on pump gas.

TTI make a 4" collectored header but that is only for the Indy 426-1RA head, and Im running a set of Indy 426-1 head.

So, am I better off with a 4" collector or will 3.5" be sufficient ?

Any experience with this would be great !

Thanx