I have a very old (1940's probably) Milwaukee-Delta 14" saw that is pretty much identical to yours. I bought it from a guy on craigs list for 100 bucks with no motor or stand.
Like you I used a worm drive gearbox and had a 1HP DC motor and variable speed drive that I used. I can slow mine down to about about 100 SFM on the low end and go to about 1100 on the high end by turning a knob. As I use it much more for metal than wood, I can live with that. If I ever decide I need more top end for wood cutting I can add a pulley but have never found it to be a problem. It is an excellent saw and one of the most often used machines in my shop.
Question - Is the seal missing from the input side of your gearbox? If it is, you might want to think about shielding that somehow to keep dust and crud out of it. The sawdust and metal cutting get into everything!
Really nice job on the conversion, You will be really happy with yours, I'm sure.