So here's the skinny on my rig, it's desmogged with a Trollhole carb, it has 391,000 miles on it, current engine has about 130000 of those miles. It has a lil knock that kinda comes and goes. So last week I changed the oil and added 20% of MMO, drove it around a few times after work and didn't really notice any huge difference. Yeah it was quieter but I didn't drive it very much, so we come to this weekend and it was time it make a 300 mile trek to Sparta, TN to OTMT with upstate cruisers. So to get the most out of the rig I also ran it on mid grade gas (first time ever running it on mid grade) . It's a 5 hour trek and I made it on pretty much a tank of gas, I got 15 miles to the gallon this weekend, I am freakin stoked! I don't know if I'll run the mid grade around town just cause I don't think its worth it for around town use, but I will definitely run it on long hauls. Then engine ran nice and cool, actually saw the temp gauge drop when I got to the higher, cooler, elevations. Ran it between 65-70 mph and she never missed a beat, wheeled her all weekend and drove her home. I am going to put some in the tank and see what kinda results I get from it. All in all I'm sold on the stuff!