Taida 4v pistons source
 

Anyone know who sells them? They sell 4v heads but I can't find any 4v pistons and I know their valves are bigger than the Hoca/Rumia 4v heads. Thinking of picking up one of these heads and I want a piston made to clear those beefy valves..

The place that has the heads can't get the pistons?

Not one of the places I've seen selling the heads, shows any 4V Taida pistons. They offer the Hoca ones, but I'm not sure they'll work with the bigger Taida valves. I've emailed four different stores, waiting for a reply.

Taida rep from Taiwan got in touch with me, asked what bolt pattern I had (54mm/57mm), said they had heads and pistons for the 4v and would send me a list of compatible parts for my gy6..
Didn't seem to indicate small onesie-twosie orders would be a problem.

Looks to be about $482 shipped for the 4v head with 22/23 valves and a 61mm high compression forged 4v piston.

That's not a bad price, I wouldn't go over 61mm bore and forged piston is stronger.