did oil and filter this Spring using Lucas High Zinc Hot Rod and Classic 10W40 in '68 383 Barracuda. I seem to notice louder engine noise like tappets or lifters lately. Car moderately driven, no more than a 150 miles on the new oil. Very hot summer - wondering if heavier oil would be worth a try. Oil level adequate, pressure OK. I did actually add a half quart more than dipstick mark because it seemed to not take what it should and it's a chinese aftermarket stick but I don't think a 1/2 qrt too much is going to cause me engine noise..any comments appreciated.
