I attended one of GM's first training sessions on the Qjet at the General Motors training center in Memphis in 1966 or so. It's really a very well-engineered carburetor, with a 3-stack venturi that transitions very smoothly through all the RPM ranges before getting enough airflow to move that huge air valve and start flowing secondary mixture. Depending on how far the secondary air valve is allowed to open, the carb can flow up to about 800 CFM. Its midget half-brother the Dual Jet would probably be a good choice for your engine, as most of them were designed for the 3.8 liter (231 cubic inch) engine and it would only be jetted slightly over-rich. Adapting it might not be be a big hassle, since the manifold already has a fair-sized squared-off hole in it.
Jerry
