Lugnutz, glad to see you are on here! I used your website quite often during the rebuild. I am running buckets so I stayed with the traditional Camaro tailhousing.
I lucked out and still had the old o-ring for the speedometer cable, found a new one the same size and swapped it out.
I am taking a TKO600 shifter, cutting it down to fit, and rewelding it together. The width spacing on the bolts is perfect, just have to cut out about 2 inches of the base, tack together, add 1/4 strips on the sides, and weld it up. The shifter rod has the same geometry as a stock shifter, but doesn't stick down far enough. I have a machinist friend who is turning it in a lathe so the bushing fits up about 3/4" higher, which will put the shifter at the perfect length AND give me a shorter throw! Hopeing it'll all work out, when the rear bolts are in the TKO600 shifter with the rod removed, you can see it lines up perfectly. I will post some pictures when I get the parts back from my buddy and assemble it.