Hey from the front your picture looks just like the panel "delivery trucks" that were so common when I was a kid-50's 60's.
You managed to put a modern drivetrain in it-and get great mpg-wow.
Makes me wonder if I should replace my 220,000 miles 5.7 in my 1998 Suburban if it ever gives up the ghost.Showing no sign of that now-still gets 20-21 hy-on long pure hy trips-averaging maybe 60 mph-gets maybe 11-13 mpg in pure city since my wife just drives it-no hypermiling gliding-just gas brake-kills my mpg-but not worth a fight with wife-good wife.

Any more pictures of that 59 Suburban-is it 4 doors???
PS-Anyone notice an increase in mpg lately-I suspect there is less ethanol in gas now-because the drough drove up prices of corn-ethanol etc-might not make sense to put 15% in gasoline anymore-maybe they dropped it to 5%-since oil is down in price-corn-ethanol-up in price
The ethanol hurt mpg-more than it is supposed to-for some reason-
155 should just drop mpg by maybe 3-4%-but many folks claim 5-10-15 % drop??