we just ran a 10.8:1 JE piston in it becasue we wanted to run pump gas. it had that piston and the stock sleeve was bored to that size. we also have a FCR 39mm, hotcam stage 3 cam, sparks x-6 exhaust that was thermal coated by www.swaintech.com

that was all the engine mods we have. you may not be able to find much higher compression. if so, the piston dome will get pretty tall and the extra compression it adds will not help, and may hurt, because the flow path is ruined accross the top of the piston. i would just use that piston and run thinner gaskets if you want higher compression.