thebrow89

im building a new engine 4 my 92. i got a block from a 96 and im looking for a head. i think anything from 91 to 94 will fit. does that sound right?

5-90

Your 1992 came with a 7120 head. This head was used 1991-1995.

The cylinder head ID number can be found as a raised cast number, above the #3 & #4 exhaust ports, outside of the valve cover. They are:

2686 - 1987-1990
7120 - 1991-1995
0630 - 1996-1999
0331 - 1999-2007

The 0331 had the COP/DIS ignition, and is the only head to have the bosses drilled and tapped for the coil rail. The 0630 and 0331 heads lack the sensor hole for the temperature gage/lamp sensor, but I know the 0630 has the boss for it, and you should be able to drill and tap it (1/8"-27 NPT.) I have not yet seen a 0331 head, nor have I managed to acquire one (yet.)

All of the AMC242ci heads will swap to the short block mechanically (including the 2685 1975-1990 258ci head,) but the manifolds and ports do differ. The intake ports were raised ~5/8" for 1991 (to improve intake airflow,) which means the intakes aren't a direct "bolt-on" swap - work wants doing. Also, the exhaust port decreased slightly in size with each change, so the exhaust manifolds are all different and don't readily swap (going backwards.) The intakes, however, will swap mechanically WRT the cylinder head, but the accessory mounting did change as the years went along.

98 JeepJeep

so a 7120 head should be able to be placed on a 4.0 that HAD a 0630 head with no intake/exh fitment issues?

5-90

The 7120 head CAN replace the 0630. The intake should fit up no problem, but there will be some exhaust issues (the exhaust ports on the 7120 are a bit larger than the primaries for the 0630 header. A plate can be fabbed to close up the holes, or just use the 7120 header in place of the 0630. The later intake should flow better, so keep that.)

98 JeepJeep

well darn i got a 7120 head to port and clean up for my 98. The header looked exactly the same as my 98 and also the parts store list's the same felpro gasket #??? hopefully my header will work with no issue. it is a Mopar clone header that is larger than the stock header.

5-90

If it's meant for the large range of years for HO (1991-2007, or something like that,) it should have large primaries to fit the 7120 head. The problem would be putting it on the OBD-II head with the precats (0331, 1999-2007,) in an Air Police area.

If you're anywhere near San Jose, let me know when you swap heads. I could use another 0630 for sectioning and analysis...

98 JeepJeep

i just went back and looked at the header AD it states for 91-99 so im covered. Im on the east coast so cant help ya on the head........