Thanks for your replies everyone. I made some progress on the motor swap and have the motor hanging on the frame. I made a template with cardboard then transferred it to 5 mm plywood for proof of concept. The motor is just forward enough to clear the cast intake port on the motor. Chain line looks good and I have to make a bracket for the other side of the frame. I'll bridge the two brackets together with square tubing to add rigidity. Only obstacle is the pedal shaft has to be lengthened on the fan shroud side and a high offset pedal arm will be used. There are a couple of bolts on the top of the fan shroud that can be used with custom brackets to the side cover tabs. I'm thinking a cheap 19 mm pit bike carb can be used to get it running. A custom intake elbow will be a pita but I know of a shop that fixes aluminum boat propellers and fabricates stuff. Still have to source a 28 mm header pipe and aftermarket expansion chamber but It looks promising if I can find a good welder...
