For my winter project I'm going to replace the posi unit and gears. Right now the gears are 3:08.

Suggestions for the best unit to replace it with... Eaton, Powertrax etc.

Also looking for a good link to rear diff. Id's and rebuild instructions.

Anyone got any good pic's? All input appreciated.

My vote goes for Eaton posi units.
I am opting to leave the rear end rebuild to the pro in my area because it looks like a giant headache to me.
Heres a link i found helpful in making that decision. (http://www.fullsizechevy.com/fscu/axletech/)

Thanks for the link 70Avido! That is a great link!!!

Where abouts in Mass. are you?

If your rear end has an original posi in it then it is an Eaton. You can rebuild the one that is in it. If it isn't a posi now then I recommend the new Eaton. Get a good installation kit with quality shims and bearings.