Good call on the Q-jet, and one calibrated for a 305 like my 85 C-10 runs would be just about ideal for a 292, with little or no rejetting required. You'd need an adapter plate to make it work on the Offy intake, but a little judicious blending of the adapter to the manifold would minimize the power loss from the adapter. I attended one of the first technician training classes GM had on the Quadrajet in 1966, and I've been impressed with its engineering and flexibility ever since. I had a Q-Jet on a 460 cubic inch MOPAR wedge truck pull engine (bored-out 440) that produced 714 HP at 6500 RPM on one carb and gasoline, and those are temperature and humidity-corrected dyno figures, not weed-induced fantasies!
In my decidedly biased opinion, the lump port conversion is only effective on a race-only high RPM application, and that setup would probably benefit from 3 side-draft Weber carbs. It would suck like a Hoover vacuum cleaner at low and midrange speeds. I'd build the engine for low end and midrange torque, and be satisfied with 250 HP or so and a 5-6K RPM top end. That's very doable without breaking the piggy bank too badly. Have fun!
Jerry
EDIT: Here's a though on that Borla header- - - -extend the pipes into two collectors where each tube is equal length to get the same scavenge effect for both manifold sections. The truck pull engine I mentioned above had individual header pipes 8 feet long each going into 6" diameter collector pipes, and the low end torque was awesome.
Jerry
Last edited by Hotrod Lincoln; 01/07/2014 2:14 AM.
