You can fit a stock HEI in the hole. Stab the dist the the vac advance pointing at 7. Get a wire set for a 77-78 TA 400 or custom wire set. If you go with stock cut wires you'll want #1 in the back pointing at the wiper motor. Also run about .060 gap on the plugs. Your also going to need a keyed 12v to the coil. I got lucky at the salvage yard 77 LeMans 301 with a newish Napa HEI for only $15.