@JB356SR posted:If I go to a 78mm crankshaft do I have to change the rods and pistons?
No, you don't need to go to longer rods- the rod ratio in a 1600 (1.98:1) is very conservative. Stock length rods (5.394 or 5.400") are used with success even in 82 and 84mm engines all the time. With VW rods a 78mm stroke engine gets a little wider (just over ¼"?) with stock stroke pistons- not a really big deal. You could use 356 length rods (2mm shorter from center to center) and it would be just a little wider than stock. Using stroker pistons you would end up with an engine a little narrower than stock.