Overdrive Unit

[Dellb]

Hi All
Has anybody got any experience of bolting a gear vendor OD unit to the back of their C3 TH350 box?
Delb

 

[Oneball]

No experience of these at all but the transmission tunnel aft of the tranny yoke is very narrow on a Vette and the handbrake mech is there too. Do they do a Vette specific kit?

Also looking at the prices wouldn’t you be better off getting a 4 speed auto box?

 

[Dellb]

There are a few options for the xtra gear, most require lots of other mods, and apparently you have to keep a weather eye on the throttle relationship.
I just found this option that only requires a prop chop.

 

[Oneball]

There are a few options for the xtra gear, most require lots of other mods, and apparently you have to keep a weather eye on the throttle relationship.
I just found this option that only requires a prop chop.

I’d be very surprised if you didn’t have to modify the transmission tunnel, I’ve been looking at updated propshafts for my C3 and some of the bigger UJs will foul on the tunnel/handbrake mech.

 

[Roscobbc]

As mentioned C3 transmission tunnel is tight - propshaft will also need chopping and then being so short the angle of all respective parts, so engine - transmission - OD unit and pinion all become critical. Before the Gear Vendors unit was available back in the late 60's /early 70's there was the Hone-O-Drive unit which had mechanical engagement rather than electronic (Gearvendors) - Baldwin Motion C3's sometime used this but only with manual transmissions.
Surprisingly the Gearvendors units was a UK designed product bought-out by them when the UK manufacturer folded.