If I was absolutely stuck with a shorty header I would get or build shorty headers with a 1 3/4" pri pipe
if I wanted to use that and the 3.55 gears I would have supercharged the motor.
850 950 carb Weiand 142 or 177 blower 3.55 gears , big exhaust big tube shortys.
Your roller cam is good. low engine compression ratio.
That would G L H.