Is there a difference for the bell's brg. retainer holes being one is 5.1/8" and another one being 4.11/16" for the bell/cross member mount units, both having Rubber mounts at the bell/cross member area? Are they a early and late version for them?
I don't know the dimensions, there is indeed a larger and small style used for 1955-72 trucks. The change came in 1968 with the introduction of the SM465 transmission, which required a larger bearing retainer. TThe he larger size retainer was also used on the 3 speed transmissions. Before 1955 there were also some differences in bolt pattern and hole size, but I think you are not talking about them.
So then up until 1968 the bells had the smaller brg retainer hole (4.11/16") and 1968 on up started the larger brg retainer hole (5.1/8") OK. Why I ask this is the parts lot I bought has a small hole bell with two bell/cross member mount pads for the horse shoe type rubber mounts and a 5th hole Saginal 3 spd also small brg retainer, going to the tail housing it has a tail shaft trans mount for rear tail cross member mounting. Finding out I believe I have a Heinz 57 parts trans. PS. I guess some had ask for more numbers which I later found , here it is-S4A19 below side cover right lower side, stamping numbers and letters.
I have the small hole V8 cast iron truck bellhousing as you described in my truck with a full syncro Saginaw 3 speed and don't run a rear trans mount. I probably put a hundred K on it that way. It might be the best way to do it but I have never had trouble with it. I had to hunt to find the 5 hole Saginaw info and found this thread that probably has your answers. https://www.jalopyjournal.com/forum/threads/saginaw-3-speed-help-please.531231/
The 5 bolt was used on the 73-later trucks, they did not use the bellhousing mount, they used a rear transmission mount. And the bearing retainer could have been changed some time in the past 45 years.
Can anybody tell me what this set of numbers & letters stands for, numbers and letters are from just under the side cover's lower right side stamped into the main case. They are... S4A19. So far I have been told this 5th mounting hole on top of this trans at the Bell to trans mount holes is a Saginaw nothing said about any trans build code or its RPO code, I also would like to know that. . Edited. Sorry forgot to say this trans is a Saginaw 3 spd.
It's a long shot, actually just a guess on my part. Since Saginaw 3 and 4 speeds share the same case. The "S" for sure means Saginaw Michigan. Now, is the 4 for 4 speed? (I don't have a reason as to why because side cover clearly would tell anyone 3 or 4 speed) The rest then would follow as usual.
I have another thread about a 3 spd HD truck trans this one is the HD Muncie 3 spd from 69 up to 78 I believe. It also has similar stamping in the same area, it is M0C26A. Been told from (mmerlinn.com) his web site that its a GM part number used to order that trans from a Dealer Parts Counter. Maybe my Saginaw follows the same, not sure though.
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