Jorge, I had the same problem with my 54 235. The fix was to rebuild the starter. I did this myself. The rebuild kit was purchased from chev of the 40's. I also replaced the drive gear and bushing. I honestly think that that when the starters that are rebuilt by local rebuilders they don't replace the gears all the time. When I replaced the gear and bushing the spinning and not engageing seased. I went through all this trouble due to the same problem you are having now. Hope this helps.
