What's the best way to put a neutral safety switch onto my clutch pedal for my '68 Charger?

The best way is not to. When you start the engine with the clutch pedal depressed you are putting all of the weight of the PP springs on the dry thrust bearing. Put your trans in nuetral and then put your left foot on the brake and start the engine.

Sounds like a plan, but the drag strip requires this as part of their safety inspection. Also need to add a driveshaft loop if running below 13.99 1/4 mi..

Which drag strip? I've had a couple of four speed cars on the strip and they never looked for a switch. They were not part of the car originally.

Not NHRA required.

Tracks can impose reasonable safety regs on their own that aren't IHRA or NHRA. A rule that insures that the car can't lurch forward during cranking or starting (similar to having a neutral safety switch which I believe IS REQUIRED) is one that I believe should be inforced. OEM has had clutch safety switches for at least 20 years. And I'm sure there are different opinions on starting in neutral, with the clutch depressed or not - some people don't like the extra drag of the input/countershaft spinning in (cold) gearlube on the starting system. Personally, I never believed the dry bearing - thrust face theory - I've never torn apart a running motor that didn't have residual oil in the bearings. As to your post on how to install the switch, if one wasn't OEM, I usually install a switch to interrupt the ground side of the start relay, like OEM does with the neutral switch on autos. You may have to fab a bracket.

Clutch safety switches are a hit or miss affair. I have owned an original four speed 66 Barracuda, 1980 Omni, 1982 Rampage, and we have two 89 five speed Chrysler LeBarons. NONE had a switch on the clutch. Chrysler put them on some 70s cars, but I couldn't tell you what year or what cars.

I have also seen the effects of a fairly heavy clutch on the thrust bearing in the old 66 Barracuda. I will NOT start a manual trans car with the clutch pedal depressed.

89 Lebaron had neutral switch in manual trans - they started showing up mid 80's. Couldn't start in gear. My point was there should be something there to keep from accidental movement during start. As to the clutch in/out, I put the onto my opinion and explained why - I wasn't meaning to criticize your opinion, just explain mine.

According to the factory manual you are right the plug on top of the trans is for back-up lights only, and they ground the brn/yel wire that usually goes to the neutral switch. I had an '88 Turbo Lebaron 5speed that had (an aftermarket) remote start and they must have added a switch somewhere - it would only start in neutral, with the e-brake set. So I thought they were using the trans plug for the safety switch - apparantly not.