I have the same saw (pre-blue) Lortone. I bought it about four years ago from an old coot who lived out in the middle of the desert. I should say, I bought a basket of parts from an old coot that was supposed to assemble an old LS-12. What I was able to assemble has cut me many slabs since. I hesitate to offer advice because I'm not sure my feed motor is correct. The motor inside that front box that feeds the saw is only attached to the screw shaft. While there are four mounting points on the motor, there's no place to mount it on the case nor inside the feed motor box. There is a long screw with a nylon/plastic sleeve that stops the motor from twisting inside the box, but other than that, it's just attached to the end of the screw shaft with a hex set screw. It doesn't seem right to me that it was designed that way, but it's been functioning. Like all things old, sometimes it takes a sharp whack with a blunt tool to get it motivated, but once it's going it doesn't stop. Since there's no clutch mechanism, I've determined that the feed is governed by the screw shaft release lever... when it binds, it simply hops a notch and keeps trying. Again, this seems like some questionable engineering, but it works for this backyard MacGyver. There is no auto shutoff but I don't think it would take much to drill a hole through the front of the case and attach a chain to the toggle switch. Last year I replaced the bearings and swapped the round guide shafts. The bearings were standard and I bought the set online for about 40 bucks. The round guide shafts were worn so that when you moved the carriage back and forth, it made a slight dip. Obviously from years of abuse. In reversing them, it was like installing new guides running straight and true.
My best advice is to treat it like the 1968 VW bug you had in high school. It will get you where you're going, and you can exchange parts with your lawn mower, just don't expect it to be a finely tuned instrument. As for the blade, I've only used a cheap, notched (crimped) rim blade. Put exactly 2 gallons of mineral oil in the pan and you're good to go for a season of cutting.