When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Yours is an OHV, right? Just about any OHV will work, just as any SOHC will work if you have an SOHC.
But don't replace an OHV with an SOHC or vice versa--too many things to change to make it run right.
Get a 4.0, and strip the intake and anything electrical off it. Use the stuff in your truck to replace all that. The idea being that only the mechanical stuff gets swapped and the electronics and control etc all stays the same. Same for OHV and SOHC.
But, there was a change to "better" guides and tensioners somewhere around 2002, so don't get a '98 or '99 SOHC without going through the guides and tensioners.....
Best to avoid the early V6~4.0L~SOHC engine short blocks that had a "Rube Goldberg" BalancerShaft;
that was found not to be needed and was deleted from factory engine builds sometime after 2001.