I have a 79 MX175 and was wondering if a 79 IT175/IT250 engine would fit.

I'm asking because I need to rebuild my engine and would like to purchase a rebuilt engine.

Thanks

MX175 & IT 175 from "79 look the same mounts with maybe something going on with top rear outer spacer on the IT.
Forget the 250 motor.
Just look at Partzilla like i do & open separate tabs to jump from one to other for a quick eyeball compare.

77-79 IT175 engine bolts into the frame...  much bigger carb on IT so you'll need the IT carb and you'll have to make a new air filter setup.  Your exhaust pipe will fit but you'll be leaving a lot of HP on the table...  IT exhaust pipe will not fit your frame.  Chain size is different on IT so you need to swap sprockets and/or spacers. Different ignition so some mods might be needed there to get timing right if you don't use IT ignition. (Also no Autolube on the IT175, so throttle cable and throttle from IT or other suitable model might be needed.) Lots of little details and differences but it's possible... 

IT250 is a different animal.

78-81 DT175 engine is what was used in the monoshock MX175 so those will also bolt right in and work without having to deal with a bunch of fabrication and modifications like the IT175 swap would require.

Thanks for the feedback - looks like I'll just have somebody locally rebuild the engine.

I'll also compare part numbers etc on Partzilla