I always get a kick out of these debates, they all work. Both my '69 Swinger and '71 Demon had gear oil in them from the factory, had them apart a lot from street racing. I always put 80/90 gear oil back in them. I live in northern Illinois, wonder how I ever got to work in the winter if I couldn't shift it with gear oil in them. I use Pennzoil Syncrowmesh oil now, works for me. Most of us are not driving these cars in the snow and cold anyway.
