I actually used the original pedal and bellcrank for my Crossfire conversion. I tried a mechanical linkage with a second bellcrank but I couldn't get the geometry right. Eventually I fabricated a bracket for the pedal end of the cable housing and created a cable socket in the OE linkage for the cable using
this trick .
I have used OE GM pedals like the one posted by leegreen many times. It's ok to heat the linkage to red hot and bend the linkage as needed. If the top is too long just cut it off then heat and hammer the rod flat where you need the cable to install. Drill a hole in the flat and cut a slot in the side and you've restored the OE cable attachment.