Ok another wierd thread.

After rebuilding my 5.7 vortec in my 96 chev suburban 1500 the guy who did a lot of the machine work talked me into using the Joe Gibbs Break in oil (and since I kept my roller cam untouched and reused the hydraulic lifters) for 200 miles then change the oil/filter but to go with Joe Gibbs Racing oil. He talked up the Zinc vs detergent issue and all that so I did what he recommended.

Now i've been reading that the high zinc oils like Joe Gibbs Racing oils can and will foul up your catalytic converter in the everyday non-high performance engines. I just did my initial change after the break in and am running this JG racing oil now.

Question: 1. Is this oil actually BAD for these roller cam engines and their emissions systems?
2. Should I get it out of my suburban and if so what do you recommend I run?

Thanks again Everyone.

JJ