Fresh Rebuild Questions

I just recently purchased a 1991 XJ 4.0 AW4 np242 completely stock with 189,000 miles and horrible rod knock on cylinder 1. I've removed the engine, gotten a new crank, and am in the process of cleaning her up and rebuilding it.
I have a lot of experience rebuilding modern, multi-metal, ohc, four cylinder and 6 cylinder engines, but have never rebuilt a motor like this and need a little help.
I've searched and have found conflicting information on cylinder bore specs and the lifters.
On a 4.0 from in a 1991 XJ, what is the stock bore? I need to make sure that I don't need to bore the cylinders and get bigger pistons. I've had one Chrysler tech tell me the bores change according to year and application and another tell me they were uniform throughout its production run.
The other question is whether the lifters in a 1991 XJ 4.0 should have concave bottoms. Again I've been told by different engine builders and Chrysler tech tell me they should be convex, flat, and concave for several different reasons. Mine have concave bottoms and I need to know if they should be this way or if they are as a result of wear and new lifters are needed.
I know its a long post but any concrete answers would be very much appreciated. I'd like to finish this motor ASAP so I'm hoping that what I have now will work and I don't have to wait and save up to buy new parts. Thanks in advance.

The bores stayed the same. The piston rings went from metric to standard.. or the other way around... but just get the ring that fits the piston. However that is inconsequential as the machinist should measure the bore, determine the over bore then order the correct piston.

A new lifter will be slightly convex on the bottom. You can't tell unless you hold a straight edge to it or measure it. If your lifters are concave they are trash as is your cam.

Stop talking to Chrysler techs. They know how to replace parts, not how to rebuild engines.

Thanks for the info. Looks like my cylinder bores are within spec but I'll be needing to get a new set of lifters.

Before I go out and pick up a new cam could someone give me the base circle diameter and the lobe diameter. Right now I'm measuring about 1.439" for the base circle and 1.690 for the lobe. The cam sits snugly in its bearings and the lobes aren't much smaller than the cam journals. Again I've searched but haven't been able to find concrete numbers. The only thing that seems for sure is that the cam profiles changed for 1996.

If I do need to replace the cam would I be able to just replace it with the '96+ cam. I understand that it has a better torque profile.

Again thanks for any help.

With lifters that worn the cam is worn as well. When replacing it keep in mind that around 98 (IIRC) they went to a cam with a thrust plate setup. Won't work in your block.

What are you using to measure the cylinder bores?

I am using a bore gauge to measure the cylinder bore diameters. The spec I found was 98.4 mm. The measurements were made were after honing and and cleaning.

I'd still like to get some numbers on the cam. Please understand that its not that I don't believe you, rather that I would feel much more comfortable making a decision based on empirical data. I have found strong evidence that this motor has been taken apart before and as such I don't know what has and/or hasn't been replaced.

All the empirical data needed is on the bottom of the lifter.

That data isn't published anyhow.