I know certain year XJ's had head problems. Can someone give a short run-down as to what years were good and which were bad. Also, I believe '95 was the best flowing head by a little bit. I need a new head and I want to get best one as several different years are available at the yard I went to.

 

If I remember correctly 91-95 had the H.O head. Cast #7120 Have the highest intake and exhaust port airflow. Google Cherokee H.O. head flow chart a lot of good info pops up.

 

Is this for your Nash Rambler?

 

HO heads came on the 1970 455.

 

91-99 are high outputs. Just that 7120 were for 91-95 and 0630 came in 96-99 XJ's

 

Yep 7120 and 0630 are pretty much the same.

 

Except 0630s had holes for dowels but basically the same heads

Edit... I also think 7120 heads had engine temperature sensors in the rear of the head and 0630's don't have them, they are now located on the thermostat housings instead.

 

I'm pretty sure your right about the temp sensor. Mine has in the thermostat housing so im guessing someone put a head on mine or put a different motor in it.

 

I wish I had a Rambler. This is for my '74 Gremlin with 2 cylinder blocks welded together to make a V-12.