David,
I got approximately the same measurements laying on my side and reaching in with a tape measure: 8 1/2" X 9" X 4" = 306 in^3/57.75 5.3 quarts. Add another .5 quart for the
oil filter and remote lines, and it's almost up to 6 quarts. I think I'll stay with 5 quarts as the 4" height was into the transition slope a little. I should adjust the dipstick some how; shorten it about half an inch from the top, or make a new "Full" mark, or sleeve the D.S. tube to raise it half an inch.