Edelbrock heads on a 340 with KB243 pistons

Uh, if "dad" is going to put regular gas in it you're going to have to drop your compression ratio pretty substantially, otherwise it will be detonation city. Even with open chambers and a .039 head gasket I'm at 9.8:1 with the KB243's being .018" out of the hole, and even 91 octane barely gets it done. Sure, I've got iron heads and aluminum buys you some compression because of the head dissipation, but you're going to have to be below 10:1 even with aluminum heads to survive on 87 octane. The cam will play a factor too, my dynamic compression is only 8.2:1, with a smaller cam your dynamic compression will be higher.