Good deal that sounds like your stepping up in the right direction!! I too have a older Bridgeport J-Head milling machine mine has the old style gear box power feed on it that I have had to work on several times in the past (I bough another power feed for donor parts) and I keep saying that the next time it breaks I’m going to get a servo type and put on . I have just never used one .did your just bolt right on or did you have to make a adapter shaft to connect to the lead screw or did you get it as a kit ??
Either way I think you’ll be pretty happy with the Bridgeport