heavy bog under acell

Not sure what cam you have but my j head 340 270H cam 3.23 gear 93 octane runs its best at 26* initial, 35* mech total, 48* vac adv. on ported vac. Crisp throttle, no ping.
Also Summit sells their brand of AFR kit for $165 that is made by AEM. You can dial in a carb with ease and no guessing. Every change made is easy to see. I dialed in my thermoquad and the car is running like a 340 should. Get your timing curve dialed in first, then dial in the carb.
For heat soak you can also make a heat shield to help keep the fuel bowls cooler and insulate the fuel line as room allows.