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Trans Swap Wiring Questions

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I'm in the process of a 73 240Z restoration project, currently working on an auto to manual trans swap. When I bought the car I got an engine & manual trans with it from a 72 240Z.  First:  Ther is no netural safety switch on the 72 trans, only a back up light switch.  Is there anyway to add one?  I thought one way may be to use the existing  wires that went to the inhibitor switch on the auto and run them to a stop light type switch, and fabricate a bracket the would activate when the clutch pedal is depressed.  The only drawback is that the clutch pedal would always have to be depressed, even when the car is in netural, in order to start it.

Second:  I know the 73 autos had dual point distributors with the second set of points activated via a relay mounted on the lower left fender when the accelerator kickdown switch is depressed.  Since I'll be using the single points distributor out of the 72, what's the best way to connect the wires from the relay to the distributor points? I thought I'd just connect the two wires that went to the two sets of points together, then run one wire to the single point set. Will this work or is there a better way? I guess another alternative would be to determine which wire goes to the main set of point on the auto distributor, run just that wire to the single points distributor, then tape up the unused wire for the second set of points.  The unused wire will never get power since the kickdown switch will be remove.  

Comments and suggestions are greatly appreciated.

Paul (z3beemer)


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I drove manuals for decades with no neutral safety switch. I always check the car for neutral before starting with the clutch pedal down or not. You'll only try to start it in gear once, maybe twice... 😉

In other words, I wouldn't try to install one...

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I think that most of today's manual transmission cars use the clutch safety switch, not a neutral switch.   So your first idea would match what a modern car uses.  I have a 2003 vehicle and it has a clutch switch.  If I start it thinking I'm in neutral but I'm not and let the clutch pedal up it will still jump forward (of course), just like a car without a switch.

Does the second set of points really use the kickdown switch to change which set of points is used?  I thought it was a temperature switch.  Either way, all that matters is to be sure that the points have power under all driving conditions.  Connecting the wires together should work, but there are probably other ways, like just bypassing the switch itself, or shorting it internally.

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I really appreciated not having a switch when my clutch slave failed away from home. Start the car in 1st gear, shifting is easy enough doing RPM matching. Shut the car off at a stop, put it in 1st and start the car to get going again.

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