Motor mount question. Need ans Quick...

About to head off to the only parts store in town with an idler pulley for the 4.0.
Im also picking up a set of motor mounts, but they have four different kinds from 20-45 bucks. The most expensive are designated as "interlocking". What does this mean and is it worth the extra cost?

I don't have a clue. As far as I know, all XJ motor mounts are the same except for the cushion material. Stock use rubber. Some after-market mounts are urethane, and one of the off-road companies offers some kind of "super" rubber mount. But the configuration is all the same.

Be sure the guy is looking at a mount for an XJ Cherokee with a 4.0L engine. "Interlocking" sounds like the old V-8 mounts for the SJ full-size Cherokees.