Engine swap?

I've just had a price on a water pump for my 89 gpx250.
For not very much more I can get a complete engine from a 2000ish zzr250.
My question is; will it fit? I know they are basically the same engine, but will it bolt straight into my frame - or would I need to modify something?



For not very much more I can get a complete engine from a 2000ish zzr250.
My question is; will it fit? I know they are basically the same engine, but will it bolt straight into my frame - or would I need to modify something?