A heavy C with the combo recommended should run at least 3.23's for gears with a 28" tall tire (23570R15).
Run 2-1/4" dual exhaust Dynomax Super Turbo muffs for good torque response and fuel economy.If not going with headers,use early Dakota Magnum logs or 360 logs.
Recurve the distributor for advance to come in early to move the tank.
You can get amazing fuel economy and performance by using a tuned Thermoquad carb.
When you switch your heads,roller lifters and rockers can help MPG.So can electric cooling fans.The less parasitic drag,the better MPG.
Also it is best to match the convertor to the suggested XE256 cam choice by going one step up in stall speed.

When set up properly with the right engine parts combination,24 MPG highway can be achieved.
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