6.2L pulley ratio?

[Electricsmurf]

Anyone know the Pulley Ratio for the alternator to crank on the 6.2L? I have a Diesel Tach that runs off the alternator pin but I need to know the ratio before setting it up. I am putting it on a m1008 if it makes a difference.

Thanks
Dave

 

[cranetruck]

Measure the pulley diameters (if you have access to them) and calculate the ratio, should be about 2-1/2:1.

 

[Electricsmurf]

With the motor in the truck and a brace on my left hand I don't think I'll get a very good measurement, was hoping someone would remember off the top of their head or a post on another site. I might not be able to use my hand for a few weeks at least and I wanted to test the Tach before that in case I needed to return it.