Is engine type same as engine "code"

[nightout]

I have a 1981 xs650. I'd like to get the 750 big bore from mike but it's for the 447 type. I've looked up my vin and for my "code" is 4n9. When they say type are they referring to code? And if so what is the difference between the 447 vs the 4n9? Cause mikes not helping out so much. Help is always great.

 

[TLCbobber]

if the big bore kit comes with pistons, probably does, then you'll want 447 kit to match your crank and rods. It'll be designated 447 because of the difference between 256, 533 and 447 pistons/rods.. assuming your internals are stock 447 which they probably are. I wouldn't be concerned with 4n9 on this unless I'm missing something.