The biggest issue with gas conversions on the radials is The ignition system...

About the only way I could figure was to add a pickup on each timming cam. and route it off 5-ignitions OR route 5=plugs off 1-ignition box...
I don't know if it would be that easy as adding the spark plug caps to the ignition box.... It all depends on how many times per sec. the stock ignition is capable of firing ....

The other option to get a proper ignition pickup is a to machine a gear(s) setup that runs at the proper speed....
I don't have a machine shop so the first seems more possible..