Probe SRS piston Cyl clearance

Hello, I found some Probe SRS pistons stashed back side of my shop shelf. Purchased back in 2008'ish and not in the original box trying to figure out cyl clearance. Old catalog says "Tight running clearances" these are made from 2618-t61 Forged Aluminum I always ran 2618 pistons on looser side .004-.005 with my blower and methanol fuel setup.
Maybe it is the t61 to run them "tighter" ?
Anyone here have experience with Probe SRS pistons? Before they closed.

thanks for the help.

Reach out to member Mark O'Neal , he owned Probe.

He’s actually back in business

Vigilante Performance. He also sells Racetec/Autotec pistons like you.

rmcomprandy wrote:

dfree383 wrote:He’s actually back in business

As "Renegade" and Ross is making his pistons.

No. I don't know who Renegade is but it isn't me.

gt350hr wrote:  Vigilante Performance. He also sells Racetec/Autotec pistons like you.

I also sell JE, Wiseco, and CP. Actually, I sell whatever fits the application.

And I never stopped doing business. I closed the plant, because a corporate owned company was selling pistons below cost to get rid of me. I know this because they told me. I'm not a 60 billion a year corporation and I'm not stupid. Therefore.......they wanted the lower cost market segment and now they have it. I also sold Coast High Performance because I didn't want to build motors anymore....hence Vigilante Performance. But I took up with a younger partner and we're heading back in that direction. So....here I go again.....

For the OP. The pistons have .004 built in at the gauge point, which is .500 from the bottom of the pistons. However, clearance depends on application, so it could need as much as .006.

Mark O'Neal wrote:

gt350hr wrote:  Vigilante Performance. He also sells Racetec/Autotec pistons like you.

I also sell JE, Wiseco, and CP. Actually, I sell whatever fits the application.

And I never stopped doing business. I closed the plant, because a corporate owned company was selling pistons below cost to get rid of me. I know this because they told me. I'm not a 60 billion a year corporation and I'm not stupid. Therefore.......they wanted the lower cost market segment and now they have it. I also sold Coast High Performance because I didn't want to build motors anymore....hence Vigilante Performance. But I took up with a younger partner and we're heading back in that direction. So....here I go again.....

For the OP. The pistons have .004 built in at the gauge point, which is .500 from the bottom of the pistons. However, clearance depends on application, so it could need as much as .006.

Mark, What do you mewan built in?

The pistons are .004 smaller diameter than the bore of the block at the measure point .

Thanks Mark for the reply, a couple of holes are right at .006 . This is a spare engine methanol-w 10lbs boost I hope it lives.

Sad that a factory in America closed, I hope all employees found suitable work.

Kobelco wrote:Thanks Mark for the reply, a couple of holes are right at .006 . This is a spare engine methanol-w 10lbs boost I hope it lives.

Sad that a factory in America closed, I hope all employees found suitable work.

.006 won't hurt a thing