Now it is soooooo easy to get Redline at the local Advance Auto. ANd my friend who works there sold me 5 qts at $6.00 instead of the $7.68 ? anyway. all they had at that time was 5w30 and 20w50. So, I went with the 5w30. This is no **** guys. I have never had this much of a fuel milage inprovment with an oil. My question is.,they have all visositys in now. I think the 5/30 Redline could handle the summer heat with no problem. Or should I dump a qt and add a 10/40 or a 20/50 to the mix? I know I said I was done with synthetic, but I had to see for myself what this Redline does. Does kind of resemble maple syurp, kind of smells like it too. Maybe I can use the rest on the Hot cakes in the AM. .Frank..... Still Expairmenting in Michigan. PS. I am now using the New Napa circular flow oil filter. Still made by wix. Seems like a nice filter for the 3.00 bucks. The only reason I ask, is my truck has 140,000 on it. Burns NO oil. Leaks NO oil. Cause I ain't dumping 4 1/2 qts of Redline at the moment, ain't gonna happend.