Replacing head on 77 kz1000

Hello,Can anyone tell me if I can use a head of a later model(79-81)engine if i use the cams from the 77 head that is on the bike now?I figure i will also have to use a 77-78 cam chain.
Also what does a "j" motor model mean?

Thanks

Hello....whats wrong with the head you have? Might be able to fix it.

Just rem thinking you can purchase a 30+ year old used head...bolt it on and life is all good dosent happen offen if at all.

A reconditioned bolt-up head that will give 10's of thousands of miles could run $700 +

79-80 are pre J heads. The problem you can face is the crank. There are two cranks....one has a 15 tooth gear that drives a 122 link chain to run cams.

one crank has a 16 tooth gear that drives a 124 link chain to run cams. These are regularly found in 79-80 engines. They were called emission head. The markII engine along with some LTD models had the 16t crank and emission heads.

The J-head 1981-up. You have to do some tweeking to use on a KZ motor. I know compression ratio is on of the problems.

Yes you can run a 79-80 head on your 77. Just need to make sure you use your orignal cam sprockets that came off the 77 head. Like 4thekz1000 said theres a diffrence in the years. Also you wont need to use a diffent chain unless yours is wore or stretched. I believe the only 81 models that you can use are police bike engines. A easy way to tell if its a j head is to look and see if theres a bolt running thru the valve cover cam end cap. If there is its a j model head. And J model heads require special adpters to make it work on a earlier kz.