I get 20 on the highway with a 261 bored .030, GM 89mm transmission (.73 overdrive), and 3.50 gears in a Ford 9" rear end. 2000 rpm is 63 mph. I am running a split exhaust and single one barrel carb on a stock intake manifold.

Remember 9-11-01--God Bless the USA
JUSTICE, not REVENGE, will prevail

1951 Chevy 1/2-ton Pickup truck