i am asking the chior a question... unless Doug wants to answer...anyway, i am running a weber 38/38 with a DC intake, mild cam and oversize valves.....my question is....dutra duals y'd into a single header pipe vs ported stock exaust manifold with a larger exhaust pipe . can any of you indicate about how much i will notice in performance and engine run??? I want to go to them but, as you all know money to there will have to have me cut somewhere else on my car....everyone involved with Doug's duals...give me some thought and respond thanks all GRT

I actually can't comment since I went from 'fat' single exhaust with a stock super six setup, to a hyperpak with dutra duals...
Either exhuast worked fine in both applications, but the 4 barrel has more 'potential' than the 2 barrel did so it's 'unfair' to say one is better than the other based on what I know. I also have driven a Dart with Dutra Duals dumping into a single collector and branching back out to dual exhaust and it seemed to work OK too.

But either version was much better than the stock Feather Duster Exhaust system.

-D.Idiot

Dual manifolds gives you twice as much seperation time between the pressure pulses and then a well designed (Flowmaster) "Y" gives some scavaging. A pretty good combination over-all.
DD