A cheaper way to get HEI without resorting to a completely aftermarket (expensive) distributor would be to go with an electronic conversion from Pertronix. Guys with these in the Chevy 6's really like them and have not had any problems that I ever heard of. I believe its around $75 for a SBC. Uses a stock point type dist.
Making minor "adjustments" to the body should not be anything to loose sleep over, just make sure that you do it in an asthetically pleasing way, or you will ruin the resale value later on.
As for Danchunk, I restored a '66 Malibu a few years ago, and thier catalog had the most expensive prices out of about 10 catalogs I had. If you haven't allready, get a copy of Hemmings Motor News and order every catalog for your car that you can find and do some comparrison shopping.