2bbl conversion for slant six
so you've decided against a V8 swap at the moment?
carrying on... as hotrod swinger noted, you'll need a 2bbl intake and the proper linkage to operate the carb and kickdown for the transmission. the bouchillion kit is a nice piece and works well; it's a few bucks but well worth it to avoid the hassle of cobbling something together that half *** works.
the intake is a little more difficult. you'll either need to track one down and cough up the dough-- but they come up here fairly often. or... you could modify the existing manifold. here's one example from slantsix.org
https://www.slantsix.org/forum/viewtopic.php?t=15873
and x2 on what RRR said on the stock 360 holley-- go with a carter BBD.
good luck!