Slight update here and bump...

The heads are off. Looks like the pistons have a very slight pop up dome rather than being completely flat top as I suspected. They also appear to be slightly down in the hole, which is a bit confusing and doesn't help with CR calculations. My best guess based on a bunch of research on these engines was roughly 9.0:1 or 9.5:1 if everything is stock. Since I was expecting flat top pistons with these heads and ended up with slightly domed top, I'm not sure what that does to my estimated CR. Here are the values I used just now for my CR calcs on Engine Compression Ratio (CR) Calculator :

bore 4.125
stroke 3.760
comb. chamb. size: 97cc
piston dome vol. .012
piston deck clearance 0

...which brings me to 9.0 => 9.2 to 1 compression

What do you guys think about that? Does it seem accurate? Any pointers on exactly how I can get that even more accurate?

Still looking for some input here on whether to go with larger valves ( other head mods within reason and reasonable $$ ) and some cam suggestions.

So far, using CamQuest, I'm getting 270h and 280h recommendations with 110LSA and the about .51 lift. These are calling for headers, gears and stall as well.

Thanks,

-unix