Jeep Strokers

Hey everyone. I just got a FREE 4.0 engine out of a 91 MJ. I am going to be putting it into my 99 XJ. My plan is to make a 4.6 stoker in like a year time frame. I was going to use the head off my 99. Will it work? I Have been on many forums before and I hate probably 80% of them. Everyone was just stuck up and insult people for asking questions. I am a newbie to the whole stoker build but not to a basic OEM engine rebuild, I have been floating around with the idea for a while now. I got this recipe off a site on someones profile. What I am trying to create is something with a good amount of horse power but a lot of torque. My limit is around 2000 bucks give or take. Tell me what you think... And also where I could buy most of these parts at? And what the heck is a quench height?
Thank you everyone for your help on this.

4.6L Low-buck, low CR "rockcrawler"
Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Silvolite UEM-2229 +0.030" bore pistons
Increase piston dish volume to 30cc
8.75:1 CR
CompCams 68-115-4 192/200 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mill block deck 0.035"
Mopar/Victor 0.043" head gasket
0.058" quench height
Ford 24lb/hr injectors with stock 39psi FPR for '87-'95 engines, stock injectors with stock 49psi FPR for '96 and later engines
240hp @ 4700rpm, 315lbft @ 3000rpm

Option 2: Same as "rockcrawler" except:
Piston dish volume 21cc
9.6:1 CR
CompCams #68-231-4 206/214 degree camshaft
Ford 24lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines, Ford 24lb/hr injectors with stock 49psi FPR for '96 and later engines
264hp @ 4900rpm, 324lbft @ 3500rpm

Make sure the 91 block will work in 99. I'm sure someone else can chime in the differences in the blocks...something about engine mount holes in the block

I hope it does or its going to the scrap year. Anyone know?

There are minor differences, but AFAIK it will fit. Since you want to use your 99 head, the problems with manifolds and coil pack mounting is also non-existent. What you probably will notice is the different oil pressure sensor location (but you will most likely be able to use the earlier style sensor on your XJ). But wait for someone who is 100% certain to chime in, I wouldn't like to mislead you.

The Quench height is the distance from the top of the piston to the head surface. It acts like a pump that forces the air from between the piston and head to the piston dish/combustion chamber. This makes the turbulence that reduces pinging and makes burn process faster, therefore creating more power. You can't go too low though, since pistons will hit the head.


The only thing that I can advise you is to read A LOT on this subject, because though this forum is a great support, only your personal knowledge will help you to make the stroker fit your needs. On my first stroker for example I had some knowledge, but we were doing things as fast as possible (my friends engine died, so we wanted to get his rig back on the road ASAP, since it was his only DD), and we screwed the dynamic compression ratio. The results are horrible, power loss is huge, and now we have to change the camshaft, which is quite a lot of money and work wasted

mendelmax, thank you for your reply. It doesn't have to get done right away so I am in no hurry. I just need to know if I need to get a newer block before I send it to the machine shop.

Yeah, I understand, just wait some time, someone for sure will chime in. Or simply take a look and search for differences. Another thing that crossed my mind is that 99+ use belt tensioner- I'm not sure if the mounting points for is are the same as they were earlier. I know for sure, that AC compressor has different mount that is fitted into the head, but since you want to re-use your current head, you won't have this problem.

I've never seen a difference between any 4.0 that couldn't be solved by swapping a part or two... accessories included... That's not to say their are none. I've never had my hands on anything newer than a 2001... If he's using a 0331 head (99+) then he wants the newer belt setup, the newer PS pump to go with the 99+ intake manifold...