Let's put a stake through the heart of the early-to-mid '65 Muncie 4-spd speedo takeoff myth, as it applies to Corvettes and other Chevrolet passenger car transmissions.
This appears to have all started with Allan Colvin's books, wherein he states that the changeover on use of the '64 extension assembly (ie. tail housing) #3846428 (ie. cast 3846429) for the first half of '65 4-sp Muncie production (for all Chevrolet divsion use) happened in mid-February of 1965.
Here's why I maintain that this is not correct.
Chevrolet Service News (Sept '64) -- 1965 Product Features; Transmissions; "The Chevrolet four-speed transmission extension housing and mainshaft are revised to provide for a right hand speedometer take-off connection. The Chevelle, Chevy II and the Corvette .... four speed transmissions have revised extension housings also for the right hand speeedometer drive location".
'65 Corvette AIM; UPC M20, Sheet 4 has NO revision record around February 1965 for a switch from a driver side to passenger side speedometer drive connection.
NCRS Tech documents: Surely a major noticeable change of speedo cable length, location through and across firewall, grommet revisions, clip locations, that would be required with a switch in sides of the transmission attachment for a full half of MY production, would be documented in the '65 TIM&JG. No such mention.
July 1965 P&A30 parts catalog: shows only part # 3846428 for '63 and '64 Muncie 4-sp; '65 w/4.sp is 3857583 (ie. cast 3857584); ie. no overlap with early/late '65 designations.
Personal experience: I've owned two '65 Corvettes produced prior to Feb '65, #04835/P0829 & #014xx/P0916, and they both had "584" extensions. In fact, I've never seen a 4-sp.'65 Corvette with a driver side speedo take-off.
The "429" 4-speed extension continued to be produced and assembled on Muncie transmissions at least until 1969, to accomodate other GM division requirements, according to their speedo take-off design. (ie. Pontiacs, maybe others).
This appears to have all started with Allan Colvin's books, wherein he states that the changeover on use of the '64 extension assembly (ie. tail housing) #3846428 (ie. cast 3846429) for the first half of '65 4-sp Muncie production (for all Chevrolet divsion use) happened in mid-February of 1965.
Here's why I maintain that this is not correct.
Chevrolet Service News (Sept '64) -- 1965 Product Features; Transmissions; "The Chevrolet four-speed transmission extension housing and mainshaft are revised to provide for a right hand speedometer take-off connection. The Chevelle, Chevy II and the Corvette .... four speed transmissions have revised extension housings also for the right hand speeedometer drive location".
'65 Corvette AIM; UPC M20, Sheet 4 has NO revision record around February 1965 for a switch from a driver side to passenger side speedometer drive connection.
NCRS Tech documents: Surely a major noticeable change of speedo cable length, location through and across firewall, grommet revisions, clip locations, that would be required with a switch in sides of the transmission attachment for a full half of MY production, would be documented in the '65 TIM&JG. No such mention.
July 1965 P&A30 parts catalog: shows only part # 3846428 for '63 and '64 Muncie 4-sp; '65 w/4.sp is 3857583 (ie. cast 3857584); ie. no overlap with early/late '65 designations.
Personal experience: I've owned two '65 Corvettes produced prior to Feb '65, #04835/P0829 & #014xx/P0916, and they both had "584" extensions. In fact, I've never seen a 4-sp.'65 Corvette with a driver side speedo take-off.
The "429" 4-speed extension continued to be produced and assembled on Muncie transmissions at least until 1969, to accomodate other GM division requirements, according to their speedo take-off design. (ie. Pontiacs, maybe others).
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