When, if ever, did straight axles get a synchro for 1st gear? Do the original 57 3 speeds have to come to a complete stop before you can slide it into 1st? Thanks.
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Re: straight axle 3 speeds
No synchro in 1st for the C1s. If you practice your double clutching you can get fairly proficient at dropping it into first without stopping.
Tom -
Re: straight axle 3 speeds
Thank you Joe and Tom! That's exactly what I needed to know.
I am putting a NOM 283 in my 57 until I find a correct engine with a late January or February date.
I have the original 57 3 speed with a non-dated 450 tailshaft, and I also have a 3 speed from a 61 Vette.
I was thinking if the 61 trans had synchro I would run that until the time comes when I am able to find/put together the correct engine.
Based on your info, I'll just run the original 57 transmission.
Just thought of a couple other things:
1. Are the gear ratios the same for the 57 Vette 3 speed and the 61 Vette 3 speed? If the 61 is a close ratio and the 57 isn't, that would lead me to use the 61 trans with the temporary NOM.
2. I am using a 365 bellhousing out of a Belair. Same casting number as the Vette, but different part number. The only difference is the clutch fork pivot ball is mounted differently. The fork seems to fit perfectly. Can I use the Belair 365 bellhousing without any problems?
THANKS!Comment
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Re: straight axle 3 speeds
Transmission ratios are listed in the AMA specs that you can download from the GM heritage website.
DukeComment
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Re: straight axle 3 speeds
Mike------
The 1957 and 1961 Corvette 3 speed manual transmission gear ratios were different (except for 3rd gear, of course).
The clutch pivot stud is the difference between Corvette and most passenger car bellhousings otherwise of the same casting number. Will the passenger car ball stud work for a Corvette? I don't know, for sure. However, I would think that both studs would have to be of the same length for the passenger car stud to work for a Corvette and I don't think they are.In Appreciation of John HinckleyComment
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Re: straight axle 3 speeds
This a little off topic, but fwiw: I once mated a 56 Chevy passenger car 3 speed to a 59 passenger car 3 speed by exchanging the entire tail shaft assemblies (the 59 was shorter and would not mate to the 56 drive shaft). The 59 had a much taller first gear ratio and a greatly improved side plate shifting mechanism. This gave me a real wind out combination with the 58 Vette fuel i.e. Engine I had in the car (a 56 post 210 show car). I could downshift back to first also by just holding my foot steady on the gas which matched rpm's so I could just quickly pull the shift lever back into first.
As a side to this; I should mention that the actual shaft from the 59 tranny (brand new) had a bad needle bearing surface. The shaft was not finish ground all around the surface as if the shaft was not perfectly round when it was machined. Part way around it was raw unfinished metal. I've never seen anything like that before or since. Guess that is what parts (rejects) went into an off the shelf replacement unit back then.
Stu FoxComment
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