What piston did your machine shop install? With the 48 heads (stock 72 cc's?), and as Jim noted, shaving 0.020", you will have pretty high compression with 0.030" over stock replacement pistons - probably close to 10.5:1, maybe a little higher.
I was not aware of a "9.0:1" replacement, off the shelf piston. Did the the machine shop dish the pistons to get the 9:1?
