[ahklein]

I just finished a rebuild of my 1973.5 911 T Targa. It has 83k miles on its numbers matching engine. What started as a re-seal resulted in new bearings, timing chains, valve guides and new intake valves, new rings, oil pump upgrade, new rubber hoses. Still has original 2.4 pistons. I filled it with Brad Penn 30w Break in oil. It is running fine. How should I break it in? At what point should I change to my usual Brad Penn semi-synthetic 20W-50? I am careful not to lug the engine, but once warmed up how high can I rev?

Thank you