39 Cent... I am not sure if I misread the post above about the 37 Buick bigger car trans info. Here is what I found out when I did the "Olds 51-56 gears into a 37 Buick top shift case". - The 37 Buick gears look the same at first glance, but nothing out of the 37 will interchange with the Olds gears and shafts. The issue is that the pitch on the gears is different. The 37 uses more angled teeth than the Olds. I assume Olds engineers used the straighter tooth pitch to handle the Olds v8 torque in a heavy car. (just like the difference in Muncie M20 vs. M22) - Even the straight toothed first/rev slider gear on the upper shaft won't fit, because the internal corkscrew splines are different. They must have changed the internal pitch for torque as well. I was real suprised to see that, because the gear looks the same otherwise. -The 37 Buick input shaft is smaller, plus the gear on it that drives the cluster has the more angled pitch...so it won't interchange. - It looks like the only shafts that are usable out of the 37 is the cluster shaft and reverse idler shaft. nothing gained there. -Even the reverse idler gear ass'y is different, plus I spotted one gear that had one less tooth on the count...I think it was on the idler ass'y...or maybe the cluster. Doesn't matter, because nothing fits or works with the Olds stuff. - So the things to save out of the 37 are: -Main case -all forks,+ detent rails -top cover ass'y -Thrust washer from the cluster shaft because the olds case has a notch that keeps the Olds thrust washer (which has a bump on it), from spinning. I suppose in serious torque race engines or HEAVY cars, you should use the olds thrust washer and then put a notch in the Buick case. EDIT It's a real longshot to find enough parts to do the above mods, but the trans shifts and feels so perfect just sitting there. I do not have it in a running car yet, but it feels promising.