I think (and others would know) that this is done IAW the Lycoming parts manual and OH manual. If your engine has all the correct part #'s to make it a 160 then it is a 160. I believe the narrow deck required new case studs, hold down plates, pistons, and some possible changes to the front crank journal area.
Hi GeeBee. Did you use the 150 hp magneto timing after it was a 160 ? thanks. Jerry B.
Dont forget your crank have to meet SB 505