81 KZ650 head recommendations

I would like to practice some things I have learned about porting a head. I have an 81 KZ650H1 that I would like to purchase a spare head for and try to port it. If I do good I would like to use it on the bike. So I would like to ask what the ideal head for this bike would be? I would be most interested in a head that once ported would fit on the 650 with the most ease while still adding some performance increase.

So should I stay with the stock head or maybe a 750 or gpz head?

The bike already has the following:
Dyna 2 ignition, green 3.0 ohm dyna coils, MAC 4x1 header, coil mod, BS34 carbs

what would you do?
Thanks!!

Due to the fact that the 81 KZ650 has a HyVo cam chain, I think you might be limited to either another 81 650 head, or a 750 head.

It would be interesting to find out the chamber volume of the 81 650 head, then compare it to the 750 heads.

Since the 81 650 motor is a 750 with a smaller bore, I wonder how the head differs from the 750 heads?

wow. that is good info. I did not know that the 650 was a 750 with a smaller bore. I think that maybe I should start by comparing the two heads to see if there is a real difference. If not, I should be able to use which ever of the two that I find first. Maybe find some 750 jugs too match the head.

sorry but what is a hyvo cam chain? High Volicity?

Is an 810 conversion possible on this year 650? What head is used for that? I don't know much about other than the few posts I have read but it sure sounds like moving to an 810 creates a nice little powerhouse.

That's the easiest 650 to do an 810 kit on, all the 750 stuff just bolts on with no mods needed.

HyVo is a trademark name by MORSE meaning a link plate chain, vs the roller cam chain of the earlier 650's. The earlier 650 cam chain looks like a bike chain, yours is wide and flat.

Some people use the 650 head, others the 750, when installing an 810 kit, I prefer the 750 head, but others feel differently.