Parts required for upgrading 1.2 to 1.3

[sagaboy]

On behalf of my friend. He asked, what are the parts required to upgrade his 1970 1.2 to a 1.3 or 1.5

[sideshow]

The short answer is that it isn't worth upgrading an existing 1200, start with a later engine no matter if it was a 1300.

The long answer is that the crankshaft is different, and nearly everything that surrounds it. So if it attaches or is near the crankshaft you better plan on getting another.
64mm to 69mm crankshaft
Clutch generally gets bigger (spare lecture about 6v to 12v)
Rods require larger pins
Pistons might be the same bore (assuming replacements), but take larger pins
Heads could interchange but no 1200cc heads are as good as the later 13-up
Intake is wider and ports larger
Exhaust system is wider
Cooling system is close, tin is close, but subtle differences favor the later (about 1/4 inch at the blower)
Generally speaking the case/oil pump/cam bearings could be kept, but this is best left to experts. With your talent, you just want to use the late case/oil pump.

[sagaboy]

sidesshow, thanks for the info hopefully my friend is reading this message