What throttle to use for a 392 with 6071 supercharger

[remcolent]

I'm building on my 392 hemi
Some specs are: 8.5 to 1 compresion ratio
13 PSI boost
cam valve lift 0.519
duration 290 290
lobe sep 114
Heads only some material removed from the ports.
Valves standard siece might go for larger exhoust ports if it is worth the efford.

Engine will be propane powerd.
Will be using a megasquirt ECU and 16 gasious propane injectors.
To calculate the diameter of the trothle body's I need a rough HP estimate.
Whoud would a decent gues be
Regards
Remco