What oil/oil filter are you guys running in your stock 340's?

I took my 68 Barracuda 340 4 sp to a car show Sunday and noticed lifter tapping for about 15 minutes before some driving and engine heat-up quieted down the motor. This was the first time I had the car out since winter so it had sat for 7 months without being started.

My 340 is stock and I think the prior owner had rebuilt it at some point so I don't know how many miles are on the motor. The motor is pretty clean with no leaks and doesn't smoke and runs pretty strong so I think it's been rebuilt at some point.

Does anyone have an opinion on putting the new synthetic oils in a stock 340?

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