Bump for your question .. that's the oil I've been using for years ..
I've been looking at redline
and royal purple ..
being redline the winner so far ..
for the OP .. did you still have or you vehicle have the vacuum tank .? what you need to test from the pump to the booster it's the vacuum all the way to the booster by each step ..
man .. how much I hate those alt vacuum pump setups !