$4k is a lot of love for the engine. I'd look at any other option. Swap a used one in for a couple hundred and the hell with the gas mileage. You gotta put a lot of miles on at 16-18 mpg to make up $4k. Have yours rebuilt with a hotter cam, intake, headers, and a Weber carb for maybe $2500. Get the low mileage fuel injected one as suggested and fight through the wiring headache.