Kick-down Switch Turbo 400

If you have the Turbo 400 gearbox, the standard switch is a pain in the a... need to put your foot through the firewall to get the spring to move, and even then if the switch is not adjusted properly still won't work. 

A better idea is to remove switch from throttle cable, get a plate (or make) same as for the throttle enrichment switch on the right hand side of the pedestal, install under two nuts on left hand side with switch plate to front with switch mounted on. 

On the round throttle plate where the linkages connect, there is a lug on left hand side with a hole, bolt a bent piece of metal under this lug, so that when you open the throttle to about 3/4 open, it activates the micro switch. This then activates kick down before full throttle opening, much better response.

I used this set-up successfully for 6 years before installing the GM 700 gearbox.

Gearbox Replacement Stage 01

Have changed the diff from 2.88 to 3.54 and upgraded to the 4 speed GM Turbo 700 auto box from a VN Commodore which gives 120kph @ 2,000 RPM, and a pretty credible top end speed!. 

Also installed a 2700 RPM stall converter and shift kit, really gets up and boogies now, with a hand held stopwatch, 0 - 100 kph is 5.65 secs.

For the adapter plate and GM 700 gearbox to fit, the original large starter motor must be replaced with either a later model smaller one or a small geared type.

Adapter plate to mount Turbo 700 box onto V12. Starter motor holes were tapped, holes in new smaller gear drive starter were cleaned out so that bolts were inserted from front edge into adapter plate, allowing for easier removal if necessary. 

The standard Commodore rear gearbox mount can be used, however I designed a different rear gearbox mount and had it fabricated to enable 21/2" exhaust pipes and crossover pipe.

The standard Speedo drive, same as the Turbo 400, is used, just changing the little plastic gear for correct Speedo reading.

The standard existing gearshift cable is used, only having to change the plastic plate to show 4 gears instead of 3.

I have put a lock out plate to prevent selection of 1st gear so cannot select it accidentally when changing down manually.

An adapter bracket has to be made to connect the kick down cable to the throttle pedestal.

The Turbo 700 has a lock up on top gear which is terrific, it's where the fuel consumption savings are made. It switches on and off with a manual switch, but I am looking at making up an electronic one that after switching on, disengage operates off the kick-down switch with auto reset when cruising, and off the brake switch with manual reset. 

Gearbox Replacement Stage 02

Have added a Gear Vendors overdrive unit to the Turbo 700, and changed the diff ratio to 4.27:1.

With a 2700 stall converter, that should help to get her out of corners a bit quicker! 

while the overdrive will keep revs to 2000 cruising down the freeway at 100kph.

The transmission tunnel had to be widened 25mm aft of the gearbox to accommodate the overdrive

600mm long tailshaft