Carb and Exhaust…

I have a ThermoQuad on my mildly-heated 318 (Lunati Voodoo 256/262, 302 heads, iron 360 intake) and I'm considering swapping the intake and carb for an Edelbrock Performer and 600 cfm carb because the TQ doesn't run too well (secondaries a bitch to tune, uneven idle, just old in general). Would I see much of a difference in gas mileage because of the bigger squarebore primaries on the Edelbrock carb? Right now I'm averaging around 16-20 MPG and would like to keep it around that.

Also I am still running the awful stock single exhaust system. On a setup like this (with stock manifolds too) how much of a difference will a good dual exhaust make (such as the Pypes 2.5" X-pipe system)? I hate looking at my car from the back and seeing that dinky 1.5" pipe poking out under the bumper.
Author: admin