A\C heater box vs non A\C heater box

The ac box in that year range shadows the bulkhead connector. You will probably need to modify the air box some, or go with the OEM harness. You are kind of in uncharted territory I would guess.

This is why I went with the replacement OEM M&H harnesses when I did mine. There are a lot of folks who use aftermarket harnesses with good success. However, most are “universal” in some ways. It often takes a higher skill level and a lot more work than just replacing a harness with one that looks just like it. You can, however save some money.

As already mentioned above, mopar in those years had a separate harness for just about everything:
A/C
Wipers
Backup light / Neutral start
Console
Dome light
Accessory light group

These are in addition to the under hood and tail light harnesses.

I don’t know which of those all are included in your new harness. So you will likely need to do a lot of electrical work.

Switching an AC box for a non ac box will snowball on you quickly. There is a lot involved, and you will quickly regret it. The box you have in there, as mentioned above will work if you just get power & vacuum to it.

After market heat and air will set you back about $2k by the time all the crying is done. If this is what you want, there are lots of threads about it on here.

If you are a fair electrical guy, I would say go for it with what you have. it will take some time & figuring, but it is not that hard.

If you aren’t an electrical guy, go buy the M&H harnesses and save yourself a lot of swear words & liquor.