Like Hot Rod Lincoln, I am a fan of the Q-Jet, but you are correct in the thought of the heat issue, swapping carbs probably won't correct anything if in fact heat soaking is the main problem. If I remember correctly, you have a friend that helped with setting up the manifold/carb combo you currently are running. Does he have time to check or recollection of the float setting specs in the Edelbrock? With the small engine and technically more carb than you need, the float could probably be set to a lower limit and help with fuel percolation, just a thought to help you retain the combination you already have. Edelbrock offers a decent tuning kit for their carbs, Carbking could probably recommend some fine tuning tricks. The Quadra-Jet was available in two CFM's, the 750 CFM was standard on smaller displacement engines up to the 400 cu.in. range, it fueled millions of GM engines for 20 years. The big block engines would normally have the 800 CFM Q-Jet, found at the end of the carburetor era on hundreds of thousands of GM trucks with the 454. The difference in CFM ratings were attributed to a slightly larger primary bore for the 800. Jets and needles are available for the Q-Jet for fine tuning. I had 5 GM pick-up trucks from 1967 - 1984, small blocks, big blocks, all had the Q-Jet and had VERY little trouble with them, my 1978 Vette is still running the original Q-jet, it can sit for months in the garage and I can fire it up and drive any time. I'm just giving you this info to help you get a picture of what can be done with your truck, and a little history of the Q-Jet.
