View Full Version : 4.0 HO Info?

09-06-2006, 09:45 PM
The casting # on the head is 7120 wich is a HO motor, I am trying to find the differance between the two (non HO) and HO. My buddy is saying 40 Hp but hes almost always rong.I seem to have a lot more Hp then him and the rigs are almost the same in every way I can't find any real info on this.
Any info would be grate.

Thanks All


09-06-2006, 09:48 PM
not 100% sure but I think it's about 12 horse difference.

09-06-2006, 10:01 PM
Jeep has had 3 basic versions of the 4.0 the first 87 to 90 is the renix 4.0 (a renault and bendix pairing for that one) is on the books at 177 hp the second is 91 to 95/96 is a Chrysler designed system and is much less problematic than the renix and is about 195 hp and the third is an updated version of the Chrysler injection using an OBD 2 computer system and is 195 hp but they changed up the cam apperently and its peak hp and torque come in 400 rpm lower than the 91 to 95 version.

The short block in all three are basically the same Chrysler greatly improved the cylinder head in 91 (87 to 90 and 91 and newer heads are not interchangeable the intake port placement is different) in 96 Chrysler changed the computer system to obd2 and the cam profile and in 99 they changed the intake manifold design to improve torque and they also changed to distributorless ignition.

sj-x 500
09-06-2006, 10:09 PM
but in a given year, didn't they often have a 4.0, and the 4.0 ho/sport?

09-06-2006, 10:10 PM
No in 91 when chrysler started producing them they all got badged 4.0 HO engines

09-06-2006, 10:36 PM
Thanks Nutbar thats exactly what I needed. I have a 92 And I Will be doing some bolt ons to up it a little more now.