Hello all, I just recently bought a 1973 Challenger that has been converted from a 318 to 440 and need some guidance on getting a few loose ends tied up. The engine is a 1972 model 440 Magnum. Right now, some of the gauges don't work on the Ralley dash, the tachometer and oil pressure gauges are the ones I need help on.

 

hmm...ive never dealt with a stock tach...on all of my vehicles the tach is run off of the MSD, and on my ramcharger, the trigger wire is onto the coil, IIRC...i put it on 4 years ago...

 

Just installed dash tach (from Year One) in my 70 Challenger. Black wire is ground, green wire to positive side of coil, red wire to fuse box keyed accessory.

I am using aftermarket oil pressure gauge so I can not help you there.

Good Luck!

 

I'm not sure on the orignal tach, but aftermarket ones I thought green wire went to the negative on the coil

 

I believe the negative side of the coil is correct. On the oil pressure guage all you need to do is hook up the oil light wire off the old guage to the new guage and then install the larger barrel sending unit and hook up the old wire directly to it. Hook it just like the oil light sending unit you are replacing. I believe you can order the factory guage sending unit from NAPA or Auto Zone. Hope this helps.

 

Definitely the Negative side of the coil, agree on the rest.