Engine and frame numbers

[Martinf2]

I've got a horrible feeling I've wandered into a minefield with this one but fingers in ears - here goes.
My F2 was imported but the NOVA has gone walk about and having read about the updates the F2 engine received compared to the earlier K's, I'm keen to know how to check which country / model / year the frame and engine numbers were allocated or where I can go to research that.  I may have to get another engine for it so I need to know if the guts of the F2 engine (cylinder head aside) can be accommodated by earlier crankcases and barrels? I understand the F2 frame was raked out a little more than say the K7 / F1 frames ? How was the extra compression ratio obtained with the F2? Domed pistons or thinner head gasket? This forum has already put me straight on the compatibility of the cam carriers from earlier heads (thank you)
Engine Number is  CB750E 2600237 (could be 1 on the end instead of 7)
Frame Number is  CB750F  2107695 

At your mercy    Martin

   

[Bryanj]

If you can find an F2 parts book there is sometimes a list in the front of which country got which numbers, extra compression was done by pistons but head is different as well.
There were several modifications to gearbox, especially output shaft and bearings, over the years so you need to be carefull there