I see posts regarding SM420 trans and maybe some others. I'm guessing that would be the stock trans in a 51, but could someone enlighten me about trans history, What was used when, for how long, were gear ratios changed in later years, or just the rear ratio to increase top speed. The 51 3104 I bought is 6 years older than me, but I'm feeling like when I was 16 and got a 49 F1, only better. This ones a BOWTIE!! John
