What weight motor oil is speced for 73 302 mav and how many quarts. Which I had a shop manual for all this info
Every engine can use different oil weight depending on: Weather Mileage Build tolerances (for rebuilt engines) Mods MPG requirements HP requirements RPMs all sorts of variables... 5/30 oil is recommended by the factory over the last 2 decades because it is thin and therefore gives some extra MPG and slightly less emissions on a new engine. IMO it is too thin for any but the newest engines. 10/30 is a basic multiweight that was recommended by the factory for general use, until EPA regs pushed them to recommend 5/30. 10/40 was recommended for hot summer use, or use in an engine with higher mileage. 20/50 I don't think was ever recommended by the factory. However it probably has a place in very high mileage engines, especially in hot summer use. Following these guidelines, I'd use 10/30 for most of the year, maybe 10/40 at the peak of summer. My .02... yours may vary!
Generally, the weight of oil in a car depends on mileage and personal preference. A 302 holds 5 quarts of oil. If the engine is holding good oil pressure, generally the thinner the better for lower mileage engines. As an engine adds miles, the weight goes higher. Also, in the colder climates, the W oils(5W20, 5W30,10W30, 10W40, and 20W50), the higher # oils get thicker with the colder temps. Here in Fl., you could use straight 30 weight oil since there is no large temp drops. Since zinc has been removed from practically all the oils today, I use Valvoline VR1, 20W50 Racing Oil in most of my older engines. Flat tappet engines last longer with zince in the oil, and this oil is the only one left that contains zinc. Some people also add a quart of Lucas oil treatment to the oil change. This would take the place of a quart of oil, so you would add 4 quarts of oil and 1 quart of Lucas. This lubricates the cylinder walls and prevents dry starts in the morning. It also adds extra oil pressure to the engine with no residue. Jim
5 quarts with filter change. 4 quarts if you don't change the filter. I don't remember 5w30 back in the 70's, just 30w, 40w, 10w30, 10w40, 10-20-30 Super Blend. Be sure to fill the filter with oil first, its not good to start a car with no oil inside the filter
I use 5 qts. of 10-40 in mine. If I have an engine starting to use oil, I switch to 30 weight for a while.
