I would think at this point if you are considering building the engine for more HP, but limited on funds, you should do a gasket and seal replacement "gasket overhaul" and a good cleaning. If you plan on replacing pistons then you will end up doing rings and bearing and a cylinder hone or sleeve replacement. I would look at the Edelbrock packages that are specifically for the Ford FE motors as Mike P. suggested. I went with the RPM package and gain well over 400HP. I would like to hear more about why Mike P. said to stay away from the RPM and go with Performer. I also got rid of the ford rail valve system and replaced it with Crane roller rockers and hydralic lifters. I changed the torque converter to a 2500 stall converter and went with the MSD 6AL ignition controller (part # 6420), a Blaster SS ignition coil (#8207), a MSD distributor (#8477), and a MSD wire set (#35389). Your cam, water pump, timing chain, manifold, carb., will all be part of the Edelbrock package. How this helps. I love the 390 FE. Lots of potential.