I'm actually putting together a 54 235. I just installed the Best Gasket (4519S) rope seal to their specs and rolled it as Klhansen mentioned, last week. Crank, bearings, caps, all installed and shimmed for .002/.003" clearance on all mains, had no problems with crank spinning. I did a bit of research on the main seals and watched a few YouTube vids with them being replaced with the Best Brand design and great success.
Does your motor require shims on the mains? I believe early 55's still require them, if not all of 55.
Did you test fit the crank/bearings prior to installing the main seal? I did this first, to set bearing clearance, then installed and oiled the seal per instructions.
Are # 2 and 3 caps installed and facing proper direction? The caps are labeled F and R for direction.
Here is a video I watched as a reference. I'd think the process is pretty standard among vintage motors.
