Messing with tire size and gear ratios to get the cruising speed (normally 60-65 mph) at an engine RPM range that allows for best mileage or power. you can only get certain gear ratios for ANY axle, but you can make up slight amounts of differences in ratios by swapping for a different tire size.
If you plan on spending all 6K on just your engine and nothing else, you pretty much have your mind all set and none of us can really help you any more. You say reliable motor that doesn't need adjusting by you?, and you insist on carbureted over EFI, you just contradicted yourself, there are more adjustments needed with some amount of re-adjusting to get even a brand new carb running even closely to what even a simple throttle body injector would require, and rebuilding a TBI is very simple and less than rebuilding even a Weber/Edelbrock style carb.
Last edited by M&M CUSTOM; 01-09-2010 at 05:35 PM.