I'll tease a little first. Who knows what heads these are from looking at the photos?
I/ENice heads. Whats the specs of the Crane cam?
Flat or poptop. IIRC, 9.5 with oem pistons. 9.6 with KB flatops. And whatever you want with poptops. My guess is a milled 10.5 piston for an oem head would get you up around 12.5. The down side is that if you start upping the inches, you need dished pistons. And you can't make them off the shelf. They have to be ordered special.Are those chambers for flat top pistons? Doesn't look like there is much room for any kind of a dome. I suppose if you needed more compression, it would come from shaving the heads.
Do you know the volume?
I ran an EV51 in an early 85 solid mount EVO and was pretty happy with it.
What's the threaded hole in the center of the front head? I have both sets of instructions off of the service portal and neither one mentions it. Only thing I can think of is that it was intended for a temp sensor for the MM injection.I put them on a 1996 electraglide about 6 years ago for a customer . Ev 46 cam. Stock pistons. Suppertrapp 2into1 exhaust. Bike ran awesome on the low end. You could drag it down to 1200 rpm and it would take off. Can’t say about the top I never got it over 80 but ran great. They have 12mm spark plug holes. Below is the instruction sheet.
I thought it was for a compression release at first. But its just a blind hole.Therm I have no idea what that hole is for, actually I don't remember seeing it this was 5 or 6 years ago. I know the owner of a small Indy outside Rapid City and he put them on his son's FXR a few years back. I'll give him a call. Can you post a picture?