find your local racers swap meet. the vortec heads are no longer allowed in many classes, so you can get them dirt cheap.
that is how I got mine for my boat motor. I would run between a 262 and 270 cam.
keep your compression about 9.0-9.4 and run 87 octane. if your up to 10.3 (vortec's and flat tops), then you will be in the 91/93 octane area
