Just in case somebody else does this mod with an Edelbrock carb, here are some pictures showing where I drilled the shift lever to allow full travel.
The shape of the lever (from the side), starts out level (parallel to the trans pan), then has a slight angle upwords, then level again where the stock pivot point was. I drilled and mounted the pivot point smack dab in the middle of the "angled" part, and it turned out perfectly.
Also, what you can't see in the photo is where I mounted the opposite end of the return spring. On lower side of the bellhousing, the is a small, flat cast "hump" that's in the perfect spot for the spring to mount.
After removing the kickdown lever and the shift lever, I was able to get my drill up there and drill a small hole in the "hump". I then just used the stock return spring that was originally mounted up on the kickdown linkage at the carb (from the factory), between the "hump" and the hole where the original pivot point was on the lever.