Just my opinion - but I was never remotely satisfied with the quality of Clifford products. I'd advise against. I went back to an OEM aluminum manifold I bought off of ebay, and have been pleased with it. The good news is that they're relatively cheap used, so you wouldn't be too deep in it if you did have to buy 2, or 3 even.
Agreed, I have Clifford products and they are not all that, unless you want to make super revving race engine. They are way over sized for low end wheeling grunt that jeeps need. If I don't have a cat on my system, it doesn't get enough back pressure and runs really poorly.
I have the clifford heated intake, with TBI adapter and their headers. I have Howell unit also. As I said, if I made a race engine out of the 258, it'd be great. You could look for an offenhauser unit and get a clifford 4 barrel to TBI adapter and accomplish the same end on a 4 barrel manifold choked down to a two barrel by the adapter. Offenhauser has always been reported as better than Clifford, but I've never been able to find one when I was looking for them. Also, Offy products bolt all your throttle linkage back on exactly like OEM, Clifford does not and requires an aftermarket assembly for your throttle cable. Read PITA! As stated, stay away from Clifford unless you just absolutely have to get something of theirs to fix your issues. I do not like that company, and I have legitimate reasons after buying their products.
Slow delivery, poor communication, poor tech support and just plain crummy company to deal with.
I'd go back to stock first if I were doing it again.
I do think the 80s versions of the stock 258 manifolds were aluminum. It's been a long time, can anyone verify. Mine's buried in the attic somewhere and I'm not at home to go verify at the moment. BTW, my jeep is an 84CJ7 with 258 for clarity.