The 5 and 8 used the same Fwd/Rev box.
Some colts had a 3 speed box, i doubt any colt 5's had it.
Would be a good option.
Im sure it would not be hard to adapt a 5 or 6 speed on either.
Im sure the Fwd/Rev box would handle 12 or more HP.
Im thinking that a hotted up 5hp would be pretty useless for mowing grass anyway. The more it revs the faster it goes, the more torque it needs to keep things spinning, spinning at a faster speed than any of it was designed to do.
