I called Gibbs and told them the combo and bearing clearance and they recommended the xp4 15/50. So that's what I used. I have always used a 20/50 because of all the internal leaks. Lifters being the biggest leak.
You can't fault a guy for doing what you are told. I tried to see where that 50 Is supposed to measure at but they don't give it out. Or I just can't find it.
I don't think many other oil companies would call out a 50 for those clearances but I could be wrong.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
