About a 1 cc'ish diff between those and the 1.88 version. The factory 2.02 tulip valve gives up volume in the chamber, meanwhile takes up volume in the port, more than the chamber. The same casting 915 intake port volume -155 cc w/2.02 & 160 cc w/1.88 is what I have found.
If you want actual chamber cc and not running chamber cc, take a spark plug and remove the strap, insulator, and fill it flush with some wax. 67 cc is the smallest j head chamber, one out of 4 that were 69cc..then I have a set of stock J 2.02 that are 72cc
The casting specs online are all over the place, 273& 318 heads vary quite a bit, stock 302's at 64.4 , 273 315 @66-67c , 675 @68cc