Guys, I have a 67 SS 396 325 HP ... runs solid ... burns no oil...doesn't smoke... I run 10W30 .. I have several other vehicles that I run 5W30 in ( 95 Z/28 ... 98 F150 ... 2004 Lexus ). Can I run 5W30 in my Chevelle? I am trying to simplify my shopping ... Thanks in advance .... sdt

I'd stick to 10w30. You may get away with something thinner but the risk of going too thin outweighs the benefit of a shorter shopping list ;)

The 1968 Chevrolet chassis service manual recommends 10w30 for climates that drop below freezing yet stay above 0*F. Below 0*F they recommend 5w20 which I have never seen personally.

I wouldn't do it b/c the older motors are generally set up looser then the newer, tighter motors that are recommended to run the thinner 5wt? based oils.

Our motors unless rebuilt to tighter then stock spec's were usually recommended to run 20wt from the factory so if it has been tightened up, I would stick with 10w30 or 40, imho..

ANd I usually run 10w30 in my corn-popper anyway in the heat of the summer and then drop back to the recommended 5w30 stuff as it gets cooler..

BTW, I buy 5w30 for my corn-popper as well as 10w30 and then 10w40 for the wife's car and then an odd quart of 30wt for the lawnmower so know what you mean about keeping track of what goes in which vehicle..

Not to mention different filters that I always put the car on the box especially when the kids were around with their cars too..

pdq67

Yeah PDQ, I also have a 55 Bel-Air and 77 Camaro Type LT ...I run 10W40 in both of those...both 350's. The 55 is definitely loose...smokes like a James Bond spy car... I expect to go crate engine this winter. The Type LT has a little smoke at start-up but otherwise is very solid... I am always counting how many 10W30's...how many 10W40's,...how many 5W30's...
BTW, a wife and 2 kids that drive...I don't drive them all smile.gif

Ever consider Mobil 1? Both my buckets get 15w-50 wether they like it or not!!!