Will an RM engine fit in a TS frame

I picked up an old Suzuki TS175 (83 model I think - will have to check) for free and would like to set it up to race at the local Vintage club days.

The piston is seized in the barrel and the gear shift spline has been snapped off. I wouldn't have the faintest what else is wrong with it, but the frame, tank, tyres, forks and shocks are all good.

Now I may be wasting my time and money, but I was wondering whether an MX engine would fit in the frame without any major refinement. For example an RM engine?

Any ideas?

Thanks