Solid lifters are not a problem, in fact, less of a problem then hydraulic lifters. So I would not even worry about that and run the solids. The rear main seal is the other issue. In 55 Chevy was still using a rope rear main seal on the 235. The better neoprene seal did not enter production until 56 which is the same year the solid vs hydraulic block difference ended in the passenger car line, they all got hydraulics. Unfortunately, the rear main cap is machined differently on the 55 and earlier blocks then the 56 and later blocks so you can’t retro fit a neoprene seal to an earlier block.
I have seen one block, in person, that had been converted to a different seal arrangement. Eliminates the rope seal entirely. The machine work is apparantly not complicated for a machinist who knows what he is doing (which totally eliminates me). There is a YouTube video of a machine shop out in California doing the job.
At any rate, the better rope seal on the market is from Best Gaskets but in my opinion, it is just the best of the bad. The original seals were a asbestos graphite affair while the new seals are a fiberglass graphite affair. A lot of failures and redos on the new seals. If you rebuild the motor, see if you can dig up a real asbestos seal that is in good shape. You might be better off. The other alternative is to use a 56 and later block with the neoprene seal or do the conversion.
