my stock t56 shifter was leaking and went with the hurst blackjack... still experienced leaks with the blackjack and even after Hurst sent me a replacement under warranty I still had the same leak via the inner boot of shaft of the blackjack. I tried replacing the
vent cap, but still seeing the leak, so going to try installing a simple filter vent and see if the lack of back pressure will stop the shifter leak. Frustrating...