My '52 Henry J Vagabond was originally a four cylinder without overdrive. I purchased it ten years ago off ebay (many forum members may remember) and it had 39,000 miles on it, which I believe to be accurate (how many miles can you put on a four without OD?). I drove the car 60 mph on the highway to take it to my brother-in-law's shop to have new tires put on it. It made it there and halfway home! The number 2 rod bounced through the pan and the block. When I pulled the engine, it was obvious that it had already been repaired once (the piston was knurled and there was no ridge on the bad cylinder wall). You might say it was converted from a 4 cylinder to a 3 cylinder first! A six cylinder engine with overdrive cured the problem and I've been enjoying it for 10 years now. I drive it on the highway at 65 - 70 mph all the time now. Drove it to a meet in Missouri Valley, Iowa a few years ago, put 750+ miles on it on that trip and it did just fine. Since the 1951 four cylinders (and those '51s which were converted to '52 Vagabonds) all used the 41/9 rear end I did not have to change it when I converted it to a six with overdrive. If I had put in a six without overdrive, I would've had to also change the rear end to the 41/10. Anyway, the car turned over 50,000 recently and has been great to own and drive. No regrets at all.