Ignore the overall height of the lifter body. Figure out a way to measure the distance from the bottom of the lifter where it contacts the camshaft to the depression where the pushrod fits. If it's the same, or close on both types, use the same pushrods. If not, acquire some pushrods that compensate for the height difference. There's a company that I linked to in another post that will fabricate new pushrods of any length and end dimensions that you specify.

www.pushrods.net/
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!