Ok guys I have a set of wiesco pistons and I'm about to put my engine together and found a piece of paper in the box of pistons saying that some wiseco pistons have a pin offset.

Well after some thinking and looking at the piston, it can only go in one way due to the different size intake/exhaust valves.

Am I right in thinking this?

 

The pistons aren't marked with an arrow on top or anything?

You're right though, when in doubt, the pistons should go in with respect to the valve locations. I'm pretty sure that the offset pin goes on the non thrust side as well.

 

I've never seen any aftermarket pistons with arrows on them. But yes, offset goes on non thrust side. Bigger valve reliefs towards intake side.