I am trying to figure out why. But my friend got a crate motor for his 2010 camaro from thompson motorsports....they say run 20w50 conventional only. No synthetic an no thinner oil..... according to them that's what you have to run so they will honor the warranty and say it all they recommend in a high lift cammed engine...... can anyone tell me why?

I have been running 0w30 amsoil in my gto with a .595/.608 lift cam. Should I re concider my choice of oil weight?

 

As far as the oil thickness goes it is probably because of the bearing clearances. As to the conventional oil only and I assume a high ZDDP content, I suspect this is for the warranty and break period. When I bought my short block they specified conventional oil only for the first 1500 miles.

If your oil pressure if good then keep on using the 0w30 oil.