MPG The Best Of Both Worlds
What would be the best mods to up the MPG?
I have a 73 Duster, 3400 lbs w/o me, 408 Edel heads, M1, 9.8:1 static (about 8.7 static) comp, 236/242 hyd roller, 4000 Dynamic 9.5" conv, 727 manual reverse into a 3.73 Dana.
With the old Holley 750 DP, my best ET was 12.26 and 8 mpg.
With a 850 ThermoQuad, my best ET is 12.09 and I have gotten a best of 14 mpg on the highway at 65-70 mpg at 3500 rpm (minimal converter slippage).
So... Get a spreadbore carb, esp a
Thermoquad. When set up right, it has excellent low end torque, gets good mpg, and flows enough for my motor. I love mine, but then I get to tinker with it a lot. These carbs are very sophisticated as compared to the Holley, and require a lot more skill to set up propoerly. Thus, most people hate them. Oh, and they can have slight leakage (into the manifold) issues. An A/F wideband gage is a must.
Oh, and I got the same MPG from a Edel 1406 (600 cfm) as the TQ, but it dropped my ET over a second - not enough flow.
