best choice for oil

[Redcap]

I run Chevron Delo 400 15/40w almost exclusively.

[69twotone]

I am with Bobbyford and use Valvoline racing

[F100builder]

I've always used Valvoline in my older, flat tappet motors but use Castrol full synthetic in my new roller motors (my '08 Mazda 3 commuter car). I use Valvoline 20-50 in my bump and may switch to 15-40 or 10-40. Did anyone happen to read that more zinc is not necessarily better and may cause deposits and fouled plugs? I'm thinkin' I won't switch to the Valvoline 'racing' oil as it's .20% zinc. The 'all-climate' (.11%) should do just fine. I think I'd go with the highest zinc content available for breaking in new motors.
By the way, NAPA oil is Valvoline in NAPA-marked bottles.

[Dragon]

I used to use Amsoil 15-40 but since jiffy Lube gives me company discounts and Rotella 15-40 gets put in for $1 a quart more than the stock stuff I use rotella in both trucks.

[FLATBEDFORD]

When I switched from Motercraft 5-30 (suggested in an other forum) to Rotella 15-40 my oil useage went down significantly.