[statehedgehog]

I have an 8" posi that uses the block and springs set-up as the locking diff. My question is do i have to use the ford posi additive to get good lock-up. The person who set it up said I could use Lucus gear oil and that would be enough. Needless to say I am not getting good lock-up all the time. Any help would be great, this is not my strong suit.