Quote:

dont understand how this changes stroke or ratio or anything it still gonna go up and down the same amount???

What I meant was piston and stroke ratio would be better and along with the less moving mass. 2.5mm less on the deck would need different pushrod length but i am wondering this as a way to get more out of the long stroke a15. Reducing reciprocating weight could have rpm advantages right??
Also the shorter deck with the shorter piston would make a more dynamic stroke??
This is out of my area help needed...

cant see how that would change stroke???

will this will bring problems of shortening pushrods and stuff? or not big enough diffrence

Just checked a jp site on pistons and found that the e15 have the sama e76 mm diameter as a15 but lower piston height.
a14 67.5
a15 65
e15 62.5
could I just mill the block to suit these pistons???? that would lower my overall engine weight and give better stroke ratio