Oil

Sorry guys I’m having technical difficulties here. Purchased matching #s Dart Swinger 340 4 years ago. Lots of documentation with car. Except for engine. Hand writ note saying “bored 30 over, hydraulic H cam. Purple bigger, compression ratio 10.5:1” I’ve been running VR1 20w50 based upon recommendation of local speed shop, but recently was told that oil was too heavy. Thanks guys!
I run 10/30 Valvoline Conventional and Rislone Zinc additive. I don't think you need 20/50. A 10/30 or 10/40 would be fine. Just make sure it has zinc (zddp) in it, usually 1000-1200ppm.