You can't take any of that for granted anymore. We all use aftermarket lifters and rocker arms and there is no telling what size the balls/cups will be without measuring. Pick up a cheap set of radius gages on ebay or

http://www.shars.com/products/measuring/reference-gages/1-64-1-2-radius-gage-set

Chinese tools make some things affordable for the hobby guy today that a man used to have to do without.