Synthetic oil?

[Hoofer814]

I have a 455 from a 71 Granville in my 66 Tempest. Should I use synthetic motor oil? And if yes, any recommendations? What weight should I use as well? Thanks!

 

[melsg5]

10W30 with a high zinc/phosphorus level to prevent premature cam failure. Dont think you will find a synthetic with high levels and that viscosity