Mechanic in a Bottle...Additives

I thought it would be interesting to hear about what additives, if any, do you use in your motors. I typically add "Mystery Oil" with every oil change and it does seem to hold down the smoke and quiet the engine (placebo maybe?) I will never forget, when awhile back, I added "STP" to a 37' Chev 216 cu in when an "old timer mechanic" told me that "if the factory wanted you to add that crap, they would put it in when the built the engine". So guys what do you say, using any "snake oil" in those V-12's??? ..Regards...Rock

Here in the FL heat, I use Castrol 10W-40 during the summer and Castrol 10W-30 in the winter. No snake oil needed, the oil gets changed at about 1500 to 2000 miles, any quality oil should be fine, as long as your pump is working and you can hold some oil pressure at idle with the engine at normal temp. My engine is fresh, so adding extra crap seems like a waste of time. Remember, the overall quality and additive package in todays oil is light years ahead of the oil used back in the day.

Both of my straight-8's have 15w-50 Mobil 1 in 'em. I change it every 6 months [about 2000 to 3000 miles] and no problems. One engine is rebuilt and the other never opened. They both rev better and noticeably run smoother with synthetic. I haven't checked but I feel I'm also getting better gas mileage too!

...........................Steve