head question

Is a 1981 KZ1100 head the same as a J head?
More specifically, will an 1100 head fit on my 1015?

check APES website for camchain adaptor,but it will drop your compression 1.5-2 points with kz style pistons;)

So they are the same (J head vs. 1100 Spectre)? I have this evil little plan sizzling in my head about a 1075 kit and a J head, but if I can use an 1100 Spectre head, they seem to run cheaper on Ebay, and I'm wondering why. Do they have the same flow characteristics, same cams, bolt patterns etc.?
Off to APEs...

If there is any difference it would be
the combustion chamber size.If you have
a 1980 KZ1000,you will need to calculate
your compression ratio anyway.When you
purchase your pistons hopefully the piston
maker can suggest deck heigth etc. for
your combination.

Hows the head u have now? if the valves and guides are good it would be way cheaper to port the head u have now.if u dont plan on a big motor anyway (1200cc and up)u wont realy need a j head.the bigger u go the more goodies u will need to buy $$$$$$.dont for get carbies,welded cranks,studs, springs..........just give u a heads up bro.try this linky.this guy is ausome.
www.flowbenchtech.com/porting/CRH/index.htm

Not sure what I wanna do yet. Was kinda thinkin along the lines of a 1075 or 1100. I was hoping larger pistons would make up for the loss in compression in the J head. Does APE have pop up pistons?

Post edited by: riverroad, at: 2007/08/17 12:48

riverroad wrote:

Not sure what I wanna do yet. Was kinda thinkin along the lines of a 1075 or 1100. I was hoping larger pistons would make up for the loss in compression in the J head. Does APE have pop up pistons?<br><br>Post edited by: riverroad, at: 2007/08/17 12:48

Yes

riverroad wrote:

Not sure what I wanna do yet. Was kinda thinkin along the lines of a 1075 or 1100. I was hoping larger pistons would make up for the loss in compression in the J head. Does APE have pop up pistons?<br><br>Post edited by: riverroad, at: 2007/08/17 12:48

Stock J head buys you nothing in terms of gained flow that's worth mentioning. Only 83 - 85 GPz and late LTDs had the "J Style" head with significant flow gains.

A stock J head will cost you more in parts to build the motor. If you decide to go J head, then think about going large motor with proper pistons.




Larry C

I ran a 1075 kit with a stock crank
for years with no problems.A 1980
head with stock valves and a port
job and around a .410" lift cam
will flow plenty for a 1075 street
motor.

tjettim wrote:

I ran a 1075 kit with a stock crank
for years with no problems.A 1980
head with stock valves and a port
job and around a .410" lift cam
will flow plenty for a 1075 street
motor.

IMO...one of the nicest street combos you can do to a KZ. Cost effective and the return in performance is substantial....I'm doing another one of those right now for a guy.