Cb750 frame, what engine will fit in a 78 frame

[swensy77]

I have an opportunity to pick up a 1978 CB 750 K frame with title and also an 81 CB 750 solid running engine, my question is will it fit without modification or even heavy modification?


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[CALfeRacer]

78K is a SOHC motor, and 81 is a DOHC motor. My guess off the bat is that it wouldn't be an easy swap. DOHC is wet sump, as opposed to the SOHC which has a separate oil bag.
However, having never owned a 750 I can't speak of the rough sizes of the two, or how the mounting points are set up. The best way to figure it out would be to get a tape measure and measure the mounting points on the SOHC frame, then check the mounting holes on the DOHC motor. If they're close you could probably make it work.