Let me chuck out a few thoughts.
I seem to recall that you had a rev limiting issue, that it was electronically related, and we'll assume it's been addressed.
9.6:1 Compression ratio - no way to up that this year? Maybe a head shave? Is this a fuel related issue, or economic?
By the way, what is the octane of the fuel you have available?
Assuming the intake and ports flow properly, looks like you've got room for bigger valves. 3.8 bore, correct? 6800-7000 seems doable, but the question is, what kind of horsepower will you get there? I'm thinking the short overlap on the 1365A, combined with the small valves, might choke off on the top end. Did you flow the head?
The 1644A will respond up top, probably right in the range you want it to, but you'll need more compression to exploit it.
Of course, a regrind might give you an opportunity to use those extra long pushrods -
I'm still cypherin' on this, but I thought I'd get the ball rolling. Do you know your current cam specs?
Blue always says, "Don't guess, test". You guys are in this for the long term. If it were me, and I had to make a decision before March, I'd take the incremental approach. I'd go with the 1365A, and see if it puts you where you want to be. After that, be it success or failure, the decisions get tougher and will require a more holistic approach.