1981 kz1000j head vs 1981 gpz1100 head

does anybody know the differences between these two heads 1981 kz 1000j vs 1981gpz 1100j head????

I would check with Larry Cavanaugh!
Cavanaugh racing Heads
Hes on this site ,maybe PM Larry?
Ed

The 81 GPz1100 head has the injector bosses cast into the head.


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This is the head to have 83 GPz11

ok u got my attention whats done to it.looks ported and polished ,new valve guides, valves .

I would also like to a bit about that head. What has been done too it. Are you selling and at what price? Best wishes from Denmark.

LarryC wrote: This is the head to have 83 GPz11

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I know this is an old post but.........
I have a "new" 1981 GPZ1100 motor (without the original head), I have two heads, one looks like a good condition Z1000J and the other is an 83 GPZ1100 (as seen in picture) but in a really bad state, it will require some welding etc. You stated that the 83 head is the one to use BUT the 81 GPZ has lower domes on the pistons so wouldn't that be counter productive if using this head (with std new pistons I have).
I know there is a difference in valve sizes (this is also my problem I need valves and guides for the 83 head).
Any comments to help me decide?? keep in mind the J head is ready to install and the 83 head requires valves guides and a lot of work.

I would use the bathtub head . But then you need the Pistons to match.i just put together a1981 1000j bottom end with a 1984zx 1100 jug and bathtub head. Runs good!!!

I would use the head with bigger valves . if the bigger head is the bathtub head I would use that one!!!! Even tho the other head is ready to bolt on .