i don't think they are the same but it wouldn't take that long to drop the pan pull the head and pop one out and measure the pin distance between the two.
maybe someone will chime in that knows for sure.
so i race a 3a bottom and a solid rabbit head and i now need a piston. 3a piston you say? good luck with that wihtout a new mortgage. i notice that the mk4 engines like aeg have the same bore and stroke and i "think" rod length. anyone know for sure if this piston and/or rod may fit? i have an aeg sitting here and don't really want to rip it apart if parts won't work.
thanks doxmox. i put the pistons and rods in, they fit fine and there is no issue with th oil squirters. motor worked fine with this setup. the wrist pin is narrower and the piston is less of a "barrel" type that the stock 3a pistons. this setup would appear to be lighter although i didn't weigh them.
i bought a used AEG shortblock off vortex for $50, so i got 4 pistons/rods that way. the aeg crank will not work as it is a bit longer on the snout with the provision for the chain-driven oil pump. an aba or 9A crank will work fine if you mess up the 3A crank.