Will the 400 fit the 300 frame? Just curious as my 300 only has 8.5k on it. I'm thinking there will be crashed 400s around soon.:eek:

Not a chance. The 400 has perimeter frame and engine hanging points are completely different. Also subframe, swing arm and shock bolts to 400 engine. Those areas will bump into 300 frame.

I guess if you scavenge enough of 400 frame and cut & weld pieces of 300 frame to it, that can work.

Tank from 400 also doesn’t have hump to clear backbone frame on 300. You’ll need tank for fuel-pump and EFI system. Carbs on 400 engine will lose you 5-7hp and you won’t be much faster than 300 because of extra weight over a clean 400.

Sounds like you should have both (evil grin)

Yes, when in doubt, have one of each!