Engine Oil 360 LA?

Joe Gibbs racing oil ??????? If I was riding around in circles for 500 miles, I'd use it. But in the real world of daily use I wouldn't. Racing oil doesn't contain some additives that 'street oil' does. There is more to oil formulation than you'd think.

Any oil that's listed SG on the label should work fine on an older stock engine with a flat tappet cam. Add a high lift cam with heavier springs, and you might want to do some research. [and drive yourself nuts at the same time]. Keep in mind that 340's would run 100,000 miles with oils that are not as good as todays oils. But they contained a lot of zddp.