X2. I had a rear main leak on my '67 for years because I was too LAZY to fix it. I have an automatic, though, so no issues except a messy undercarriage and smoke from oil burning on the exhaust (embarrassing). I finally pulled the engine and resealed the whole thing, and while at it, detailed the engine bay and repainted the engine. The car looks, smells, and drives much nicer now....and I can drive it all day and park it in a friend's driveway, and not leave a drop. First time in years. It's a lot of work, but, like most difficult things, well worth the effort.