Engine
Oil
For what it is worth:
I used plain old Castrol GTX 20-50 in my engine from 2013-2016 and according to the builder it was perfect on disassembly, the bearings could have been reused, valve guides were tight and bores were perfect. This engine was autoxed and regularly turned 8200 rpm. with very high
oil temps in the summer with two drivers. When we dynoed it on
synthetic we had some
oil get by the rings (we think) and it detonated and blew a head gasket. I never tried
synthetic again. I was very happy with the results considering how cheap and available Castrol GTX is. We used Joe Gibbs break-in oil and Joe Gibbs
synthetic racing oil when the detonation occurred. Engine is 498 CID and 15 to 1 compression with a solid roller cam .800 lift. Valve springs were also unchanged as far as pressures go I would use Castrol again.