Any one know the difference between a 3021339/ 329 cylinder

[Hardass]

Any one know what the difference is between the polaris 3021339 and say 3021329 or 3021202 i know the 202 had no decomp holes any thing else

 

[Goinboardin]

I have two 202's, one 329, and one 339. Right now my sled is running with a 202 and a 329 (blocked decomp hole though). Can't tell the difference at all when looking at them removed from engine or in the way they run. I thought maybe slight porting difference but nothing I can notice.