after looking at my 55 and early 45 frame its not a early 55 frame. dont have my later 55 in front of me so can't be 100% but the frame supports are different, shock mounts are not 55 and the cut out on the frame is different. this look like chassis on my early solid cab. hard to tell from the few pictures you posted just going off what i can see matches my 62/63 frame which would make since to a early 64 solid cab frame. wondering if its a 64 solid cab frame with a later model removable top cab. as that cab i believe is 65 or newer, the diagonal engine bay vent on passenger side i do not believe is on the 64 cab. just trying to help on wha i notice. i watched the auction and didnt care for the seller on either auction so your guess is as good as mine just posting what i see. measure the wheel base and that will give you a better guess. some longer springs would get you where you need to be. pretty simple really in the end of moving rear hangers. not like its s stock rig your trying to restore. looks like it will be a good driver and fun rig