If it's leaking as badly as you say so as to leave a trail down the driveway I'd look somewhere besides the rear-main seal. They don't usually leak that much, whereas a ruptured oil-filter hose or cracked fitting will leak a lot.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
