I like 4 speeds and parts to convert are not hard to find or install. I did my 59, 62, and 63. I know nothing about cams, I leave that to Don Jacks, he is a genius on them and I'd have no idea if your cam would be unhappy with a clutch.
I'd suggest you drive it and then decide if something isn't right.
An OD transmission will be good if you drive on the highway a lot, most old cars are not driven that way for a lot of miles each year. I get as many comments about the 4 speed in the big old Pontiac as I do about the 409.