If you are talking about a complete rebuild of the J heads, don't do it. The cost would be not much less than the Edelbrocks, and the Edelbrocks ootb will out perform the Js. If the Js are in pretty good shape, guides ok, seats not too recessed, etc, I would go with them. I would lap the valves to see what the seat and valve surface looks like and I would mill them to get good quench. The amount to mill would be determined by your piston to deck number and which head gasket you choose. Good quench is .035 to .045. You can go tighter, and many do, but these are safe numbers. If you mill more than .020 to .030, you will need to space up the rocker shafts or buy custom pushrods of the correct length. The intake manifold surface must be milled as well. It cost $145.00 at my local shop to mill my heads.

The deciding factor is going to be the condition of the Js, or the condition of your bank account. The quick and easy way is the Eddies.