Improve gas mileage on a 427 so ?

[6TNCRZY]

Simplest thing I don't think anybody mentioned. Install a distributor with a vacuum advance if you don't already have one. It makes a lot of difference in cruising mileage, you need more timing when the mixture in leaner and less dense.

[xb-60]

If you:
-Change to a smaller carb
-Change to EFI
-Change the diff. ratio
-Change the gearbox
-Change the cam
-Have a dyno tune

These options would help reduce fuel consumption, but would cost from a few hundred dollars to a few thousand dollars. If you spent that sort of cash, how long would it be before you showed a net gain in $ ?

Just my opinion....but the biggest influence on fuel consumption is whose foot is on the accelerator

Cheers,
Glen