Well, I have been trying to learn the differences between the 54-60, 223's when compared to the 61-64's. This all started when I was ordering rod bearings for the rebuild of my 60! I discovered that there were sometimes, two different bearings listed, dependent upon the year of the engine. Not really all that unusual but I have been curious to learn what the difference is. I contacted Number Dummy and he verified that that were two different part numbers listed.
Well anyway, in the course of doing my rebuild, I ended up having to replace my crank as my original was worn beyond hope. I have a 63 223 that had a 61 crank in it and so I had it ground to 0.020 and then ordered the bearings I needed. Since it was a 61 crank I ordered those listed for 61-64. Smart move as it turns out! I also have to use the rods from the 63 engine as well since the earlier rods will not work on the later crank!
The 54-60 rods and caps are 1.25" at there widest point with the width of the crank journals corresponding to it. The early style uses a bearing 1.03" in width. The 61-64 rods and caps are 1.06" across utilizing a bearing of 0.842", thus the mystery of two different rod bearings for the so-called "same" engine.
I sure like the looks of the older style. That extra 1/4 inch would seem to make a stronger engine! If I didn't already have a 61 crank I would definately look for a 54- 60!
To be honest, there are not many folks that I know that would be interested in this info, but I find it quite interesting to continue to learn the obscurities of what makes these sweet old things tick!

 

It's good to share info like this...never know what kind of mutt of an engine someone can dream up!

Pat