There was also a 582 special. Those would of had the peerless tranny in them. The specials are more desireable for the collector aspect, but if it were me, and I had to chose between the two and actually use it, I'd go for the regular 582. Peerless trannies aren't known for being the best. Never been around a 582 with a Briggs in it. Look at the normal wear and tear items, steering, clutch, leaks, etc. Good luck and keep us posted on what you find out. We also love pics!
