I had been wanting to run Pennzoil HM next summer. Seems similar to PYB, but with a bit more zinc. The 4.Slow should love it. Last week I went to WM to pick up a few jugs only to realize they were phasing them out. They were the only oil still on rollback since they were trying to sell all the jugs. I tried another WM (*super center this time) and only found one jug which was hidden behind the 5w20. (The lady there was nice enough to give me 5 quarts priced at what the jug would be. +1 for WM) The only thing I can think of is that its not a blend. QS Defy and Maxlife both advertise being blends. I guess the word "synthetic" is an excellent marketing term. Get it while its still on sale!