X heads

-
Granted, J-heads (with their 1.88" intake valves) can be opened up to 2.02" intake valves but having 2.02s is a pretty good indicator right off the bat if they are X or O heads. If they have 2.02s and have a J-stamping, so be it & enjoy.
 
You do not have X heads. You may still have the 915 coded numbers on the head which are the same as the X heads. But there not X heads. Other letter heads have come with those numbers cast into them.
 
Hope this pic helps. Also no 360 ever left the factory with 2.02 heads. The J heads out there with 2.02 valves, were later installed or some 340"s had j heads with 2.02 valves from the factory.:sleepy2:
 
I wouldn't worry whether they have X, O, J or nothing all 340/360 open chamber heads until the 308 casting in the late 80's have the same port and have the same flow potential. Take what you can find at a good price. If you really feel the need for a 2.02 intake valve it's easy enough to cut the seats for the bigger valve. Unless you are looking for power above 6000 rpm the 2.02 intakes do not buy you anything and can hurt the power down in the rpm's you would normally run on the street.
 
This is true and if i had it to do over, I would of put my j heads (1.88)on street 340 instead of spending alot of money of the x's (300.00) plus (800.00) in machine and some new valves. Just to say I have X heads, LIVE AND LEARN. WALT ( might help if I ever sell though)
 
You must log in or register to reply here.
-

Back
Top