Engine Location in Frame old and newer xj's

Good afternoon all, I have a question about OEM engine locations, for Renix vintage and genII xj's both 2 and 4wd. I don't have any stock XJ's on hand to measure.
Is the engine Trans in the '98 genII 2wd xj centered in the frame?
Is the engine Trans in a 88-90 Renix vintage XJ NOT centered in the frame?

On both of my '96 and '98 2wd diesel engine conversions I centered the new engine in the frame up front off the crankshaft and used the OE location for the transmission mount.. I have been chasing a rear end howl, but the axle I used was a very old '94 that was super high mileage. I put in new pinion bearings, and wheel bearings, but I must have not hit the set up correct, because I still have a howl and now a intermittant growl at low low speed. I don't have any driving history on the axle that I installed other than it had a howl before I put in the new pinion bearings

I friend who just got done converting a '88, or '90 Renix 4wd with my same Kubota engine tells me he is certain that his engine was offset in the frame. and he set his up with the offset he measured.
Now my friend has me a bit concerned that I did not use a offset up front.

I checked the FSM but If the info is there I can't find it.

thanks

IIRC all 4.0's are offset in the frame. Its not very much, just enough room for the intake/exhaust.

I can not imagine that causing your rear end noise. Its not uncommon for driveshafts to have to make up 2-4" of sideways slant in a drivetrain, and the engine is not moved over anywhere near that far.

thanks, please refresh my memory, what is iirc? So is it offset in the front only , or offset all the way back , is the trans tail shaft offset as well.
I can measure the tail shaft again. I forget what I got last time I measured. just need to wait another 30 minutes for it to cool off a bit outside.

I have 2 trips in August over 1000 miles each round trip, I will most likely open up the rear end again to check and see if there is anything visible. before I go. The little diesel likes to chew up U-joints

thanks

IIRC = "if i recall correctly"