74 Slant 6 Bogs & Stalls Under Load / 30 mph

I would think someone on this site would have one much cheaper. Heck, I used to give them away. You don't need to ditch the emissions, per se, but render it inoperable to simplify the system. Start with the simple/cheap stuff, replace the fuel filter, test the fuel pump pressure. Can you rebuild the Holley? You have electronic ignition, no catalytic converter. Adjust the idle mixture by screwing it in until it starts to drop rpm, then back out 1/4 turn. That should get you close.