I've installed two or three Super Competion + 3 shifters in one A body and I think two E bodys(back in the mid 1970s), the linkage rods from the shifter to the arms on the trannys rubbed agianst the dang tranny crossmembers is what I remember about them You may need to make(grind, cut) some clearnaces on yours so they don't rub The stock Competion + shifters didn't have that problem
the E body shifter rods are really long compared to all the other Mopar body style shifters due to the shifter mount on the rear of the tailshaft housing I bent the stock rods up pretty bad on my original Competion + shifter so I went with the S.C.+ 3, there rods have sleeves on them and they are a lot straighter to start with