dub, The best way to adjust your carburetor is with a vacuum gauge. Just hook up the vacuum gauge to a manifold vacuum source. Then adjust your idle mixture screws out until you have the highest reading. With the RV cam start out with about 12* initial and 24* mechanical (distributor weights). If it is a stock GM distributor untouched it will probably add 25* that will be fine. Total will be something like 37*. Don't add no more than 10-12* vacuum advance. Crane has an adjustable vacuum advance can kit, Crane Vacuum Advance Kits 99600-1 - SummitRacing.com
that will fit the GM HEI. This also includes an advance curve kit to bring the mechanical advance all in by 3000 rpms.