Ok.. I've been running a MB with mikuni carb, exhaust, iron mountain heads and now Im Adding the cam. I've been turning 4300 rpms trimmed out with a new hammer prop running 28 tops. i though I was running a 38 top and 48 lower. When I pulled the drive I found out that I'm running a 36 top 48 lower.

To summarize, I'll be running a 5500 BD minus the Pistons and coils, should I go to a 38 tooth top gear? If so, what is the gain loss? Any input is appreciated.

Depends on what your rpms do with the cam. Best to wait and see where you end up, then adjust from there.

Is this a CDI motor?

No its not a CDI. 2009 motor. That's what Andy at BD said as well. Thanks