My guess is that the fuel curve is way too fat for the engine.
While the engine is seeming to run "well", my guess would be that the use of a 500 CFM GENUINE Carter would produce even better 1/4 mile times (probably a reduction of one or two tenths) and significantly better fuel economy. It would not surprise me if a Carter 400 would also outrun the 750 unless you turn a very high redline.
The 4.56 gears are helping, as you probably don't stay below 2500 RPM very long.
The 340 HP/327 used a 575 CFM carb and the 365 HP/327 used a 600 CFM carb (see thread on CFM ratings
). I would find it difficult to believe that you require more air/fuel with a 292 in any state of tune than either of these two engines.
I had a 400 CFM Carter on a 300 CID 6 with stock cam but headers; and it was all the engine could handle. However, I did not have the gears that you do.
Jon.
