Installing a tach on a non-tach coil... And coil replacement options

[newyorkin]

I'm wanting to put a tach on my backhoe, I had to replace the distributor and the best fit I could find didn't have the tach cable drive.

I haven't wired a tach in a long time... Can a tach just tap the primary hot or cold lead on the coil to get a signal? There's no Tach lead on the coil or distributor.
I did a little googling, but keep finding performance brand stuff for hot rodders.

Also, I have a bunch of old coils from various vehicles, one of which happens to be a smaller coil from a TBI 350. I'm wondering if I could put this coil in place of the ancient points and resistor coil that's currently in the machine. I've seen some electronic ignition conversion kits that require changing the coil, so that makes me wonder about compatibility between points coils and electronics coils.

 

[Thunder]

You hook the Tach to the distributor side of the coil. Usually marked with -.
If you want to swap coils I would use an older type coil designed for points. Unless your coil is bad. There is no reason to put in a better one. You are not going to turn any high revs in a back hoe.(I hope)
The OEM type coil should be fine.

 

[newyorkin]

Thanks. Maybe one day I'll actually get out there and get this thing running...