My old pinion was with a 3.73 and had a depth of 2.313 as marked on the gear itself. Now I am putting in 4.10's and my depth is marked as 2.282. This is pretty significant isn't it?

As many others have stated, my plan was to just reuse the old shims and check my contact pattern since I don't have a depth gauge. However, this to me is a big difference of 0.031 inches. Shoudn't I compensate for it?

Thanks all,
Ben

 

that difference may just be the difference in the way the new gear was made. i would start with the old shim and try it.

 

You can get a pinion setting tool at summitracing.com.
PRO-66516 Pinion gear depth setting tool $99.95

 

It has been my experience that the pinion depth marked on the gear is a good STARTING point, but may not give you the best pattern. If your old gears had a good pattern and were quiet, I would re-use your old shim. I have a pinion depth tool and it is only marginally usefull.