c-2 speedometer cable location as it passes thru firewall

[Mike M.]

let me begin by stating that all 5 c-2 AIMs show the speedo cable traversing the firewall just above the clutch pedal push rod, and there is little to nothing in the JM's discussing the speedo location thru firewall. i checked our 63s and 64s and their speedo cables go thru the firewall above the clutch pedal push rod, as the AIM illustrates. i then checked our 65s and 66s and all their speedo cables utilize the same hole/grommet that the tach drive cable utilizes(just outboard of the wiper motor. my question, did all 65's utilize the tach grommet to enter the cockpit? i might add that the 65s and 66s utilize a black plastic co-plug(similar to the ones in the c-2 floorpans) to seal the hole in the firewalls of the 65s and 66s where the 63s and 64s speedo cable goes thru. mike

[Wayne M.]

Re: c-2 speedometer cable location as it passes thru firewall

.....'65 c-2 AIMs show the speedo cable traversing the firewall just above the clutch pedal push rod, and there is little to nothing in the JM's discussing the speedo location thru firewall. i checked our 63s and 64s and their speedo cables go thru the firewall above the clutch pedal push rod, as the AIM illustrates. i then checked our 65s and 66s and all their speedo cables utilize the same hole/grommet that the tach drive cable utilizes (just outboard of the wiper motor. my question, did all 65's utilize the tach grommet to enter the cockpit? i might add that the 65s and 66s utilize a black plastic co-plug(similar to the ones in the c-2 floorpans) to seal the hole in the firewalls of the 65s and 66s where the 63s and 64s speedo cable goes thru. mike

All '65 M20's (close or wide ratio) used the big grommet with the tach cable to traverse the firewall, because Chev decided to switch to a passenger side speedo take-off fitting on the 4-speeds, right from the start of 1965 MY production (not Feb '65 as Colvin says). The plug above the clutch shaft is required to fill the hole for the speedo cable, but not on automatics which also have a driver side take-off, like the 3-speed manual. (BTW, does your plug have "DOT" in raised letters ?).

[Mike M.]

Re: c-2 speedometer cable location as it passes thru firewall

thanks wayne. makes sense. mike

[Gene M.]

Re: c-2 speedometer cable location as it passes thru firewall

Mike, I seem to recall a different cable routing for three speed in 65. The cable was off white cable covering for the 3 speed. Now I have set the 3 speed on the shelf in favor of 4 speed for driving. And again change that for a 5 speed. There was a transmission speedo attachment side on the tranny made in 65. Without going out to the garage to look I can't say which side was what. But a do recall I had to change the speedo cable (length difference too) and it's routing when going from the 3 to 4 speed.

[Mike M.]

Re: c-2 speedometer cable location as it passes thru firewall

thanks gene. i remember your 3 speed vet. i think i've got the answer to my question. thanks guys, mike

[John H.]

Re: c-2 speedometer cable location as it passes thru firewall

let me begin by stating that all 5 c-2 AIMs show the speedo cable traversing the firewall just above the clutch pedal push rod, and there is little to nothing in the JM's discussing the speedo location thru firewall. i checked our 63s and 64s and their speedo cables go thru the firewall above the clutch pedal push rod, as the AIM illustrates. i then checked our 65s and 66s and all their speedo cables utilize the same hole/grommet that the tach drive cable utilizes(just outboard of the wiper motor. my question, did all 65's utilize the tach grommet to enter the cockpit? i might add that the 65s and 66s utilize a black plastic co-plug(similar to the ones in the c-2 floorpans) to seal the hole in the firewalls of the 65s and 66s where the 63s and 64s speedo cable goes thru. mike

Mike -

That's exactly what I'd expect to see. In the A.I.M., everything in the UPC0-UPC 14 section describes the "base car" (a car witn NO options); therefore, the car in the A.I.M. has a 3-speed, which had the speedo drive on the driver's side and used the speedo cable hole above the clutch pushrod, shown in UPC 12, sheet C3 (Powerglide did too). However, the 4-speed was an OPTION, and had the speedo drive on the passenger side (584 tailhousing in '65), and its cable routing is completely different, shown in the M20 option section, sheet 4, traversing the firewall and using the shared grommet with the tach cable.