Pinching sleeves and piston work
 

I have gotten a hold of someone that does this type of work (it's not the OS rocket guy..)... he has done quite a few motors and has pics of before and after work. I'll be sending my sirio .27 to him this week...if anyone is interested, pls PM me

He offers: the pinching of sleeve and piston

the above w/ proper breaking-in with heat cycle method

and other options....

He has worked on a arca and busch series team mainly on engines which has led to him doing nitro engines...on the side, so this guy knows what he's doing....