Roger, why did it seem that the Chevy fuelers had a higher and longer flame pattern that the hemi cars? Stan Shiroma I believe still holds the all time Chevy powered TF record in the Lidtke-Zeller ride at 5.86 at the 76 Irwindale Grand Prix.
The Cylinder heads - the cam profile & lobe seperation because of the lifter arrangement - the chamber and the valves being side by side made it need a lot of fuel and a lot of timing. 56 to 60 degrees was normal. Zeller is probably the formost authority and tuner there is on BBC's on nitromathane.
* Also - the Hemi had and still uses a 4.187"bore and they can get the valve size they need because of the arrangment. The Chevy has only so much space across and it limits things.