I got more "seat of the pants" power by tuning my distributor advance than I did anything else on my teen so far. I have a LD4B, a 600 Edelbrock, and 340 manifolds ready to go on. I also have a set of 302's. If I have things apart that far I might as well put a small cam in with a new chain and gears. I really don't need to build another engine but I have a roller 318 that would be fun to put together.