J Head

Zed1015 nailed it on what's involved. But you also have to pull the motor out of that chassis, you'll never get a j head or even a valve cover on or off in that LTD frame. You really need pistons (compression) upgrade if you want to run a j head, cause you will lose roughly 2 points. But to tell you the truth you won't see any difference just swapping a head and using new pistons to maintain the 8 to 1 comp. unless you change carbs, cams etc. and even then those mods move the power peak up in the RPM band, most likely not what you want for a street bike. Best advice is MTC or wiseco 1075 10.5 to 1 kit with K410 cams. Don't forget a new cam chain and manual tensioner! Money well spent IMHO.

I rebuit my whole top end with the engine in? are we still talking kz1000?

APE Jay wrote:

It will flow a lot better than your KZ head, ( Larry can chime in with numbers ) but you are not going to like the compression drop. You should run J pistons with a .040 spacer.

www.flowbenchtech.com/porting/CRH/kz-data.htm

Shaving a GPz head just for the sake of not buying pistons should be a punishable crime

Get some pistons and a mild .400 lift cam.

APE K410 or Cam Motion Z1 will work great on the street without robbing bottom end if you put some compression with them.

The more cam you put to it, the more compression you need to prop up the bottom end. There's just no getting around that.

Have fun Life is short!