Stroking an Xj 4.0L

[4.whoa]

You said you ordered the cam kit. Its just the cam and lifters, right? 'Cause(like they said) the kits w/springs etc. don't fit the 4.0 head ,just the 4.2.
I don't know anything about that clutch, but I've had a centerforce stageII for a long time and its great! I drag race and the clutch has outlasted 3 rears and 2 motors, and it holds well enough to pull the wheels off the ground

[SilverXJ]

x2 on the kit. The springs won't fit.

As for the clutch, while I haven't used it myself, Luke clutch are well regarded.

As for the crank, I would recommend a Scat crank. It should be about $300, but its new never been turned. The one from Northern Auto will have been turned and you may not get something less than .010/.010

[worthin08]

I need help i have heard the 4.0L block has top match the 4.2L crank and rods i am gonna use is this true and if not can i use any 4.2L crank and rods in my 4.0L block or what do i need to do.

[4.whoa]

What you're asking isn't clear.
You need to use the BEARINGS that match you're BLOCK, but otherwise I don't know what you're wanting.

[worthin08]

I am wanting to know if I can use any 4.2L crank and rods I am looking at getting a crank that's redone with the main bearings and rid bearings it has a 2.5 in noble it's from like a 78-85 4.2L and I didn't know if I need a specific one or if I can use any crank and rods

[4.whoa]

From what I understand, yes you can use any year 4.2 crank /rods ,however if it comes with bearings then you will have to get another set of bearings for the 4.0 block you're using because the "tangs" on the bearings are different and don't cross- at least not without modification. The biggest differences between years are the #of counter weights and the length of the front snout.

[worthin08]

I have been looking for a scat crank the only one for a jeep 4.2L i have found is this one on ebay http://cgi.ebay.com/ebaymotors/ws/eBayI ... 0549767036. anyone know where to find any other ones and i am looking at buying new 4.2L rods from qradratec but idk if i should just get a cheap 4.2l and take the rods from it and i had to get the cylinders done .040 over becasue the cylinders didnt clean up with .030 over so what size will my engine be when its done.

[worthin08]

I have a question I am getting a 4.2L crank don't I have to use 4.2L rods in my 4.0L block or can I use 4.0L rods on a 4.2L crank and the stroke still be right making sure everything will work?

[amcinstaller]

you can use your 4.0 rods if you use KB pistons. i think the part number is like IC944 or somethin like that. the exact number escapes me right now.

[worthin08]

I am using Fedrel mongol 677 cp pistons with a 4.2L scat crank but my question is with the pistons I have can I use 4.0 rods or do I need 4.2l Rods in the engine ? Thanks

[SilverXJ]

4.2L rods. Only the Keith Black 944/945 or a custom piston can use the 4.0L rod.