So I own a 1986 Camaro IROC Z with the original factory LB9. In the 6+ years of owning the car, I've always used off the shelf oil (usually Castrol GTX High Mileage or Valvoline Maxlife High Mileage) without a second thought. Recently, I've been reading that flat tappet engines need oil that has more zinc than today's standard motor oil. My car has over 115,000 miles and I want to keep the 305 alive for a little longer. Should I be using a high zinc oil like Lucas Oil's Hot Rod Oil or Comp Cam's Hot Rod Oil? Should I add a zinc additive like Rislone Zinc additive or the STP zinc additive to standard oil?

Have I just been lucky over the last 6+ years with using off the shelf oils?

I use Mobil 1 synthetic on all my cars, but I add a zinc additive on the flat tappet cars, just in case. Probably overkill. Maybe some of the smarter kids can comment.

Which Zinc additive do you use? I was leaning towards Rislone because it's on sale for $5.

I can't remember, might be Rislone.

Rislone has been one of the long time good products on the market that you just dont hear about. i ran that in all my old flat tappet camed vehicles for years.
You need to check to see if they are still putting the zinc in the Rislone though. havent used in a few good years now.
But yes, you should run an oil with high zinc or a good oil with an additive. On a new engine you will wipe the cam right out without the zinc so why would you not use it after break in on a flat cam? I certainly wouldn't.

"GM first began installing roller cams in some Chevrolet small-block, V8-equipped cars in 1987. But OE roller-cam installations in trucks didn’t occur until 1995. So, assuming it’s stock with the original, unmodified engine, your 1986 GMC would have a flat-tappet cam. If the engine is broken-in and running fine with the stock, mild cam, high-ZDDP-content oil shouldn’t be needed and could shorten catalytic-converter life (if that’s a consideration in your area). High-ZDDP-content oils are a good idea with hot rod cams that have more aggressive lobes and higher spring pressures than the stockers or as an initial break-in regimen on any newly rebuilt, flat-tappet-cam-equipped engine."


https://www.hotrod.com/articles/pit-...k-roller-cams/

Good to know. I guess I have been using the right oil all along.

Amsoil Premium Protection 10w40, 20w50, or any of their Z-Rod or Dominator oils. We prefer the 15w50 Dominator race oil in our high performance engines. My stock 86 flat-tappet engine I run the Premium Protection 10w40. It is designed with higher ZDDP content for older engines.

GD

I use this, but would have no problem using Rislone either. But Competition Products just recently had a great sale, so I stocked up. I also use it in my lawnmower and snowblower.

Rotella is a safe oil to use with flat tappet engines. It has zinc in it already.

Today's motor oils have the same levels of ZDDP that they had in the 1960s. You need more for initial cam break-in.
After that, you should be fine with any off-the-shelf brand of motor oil. If you are running stiff valve springs, you can always mix a ZDDP additive with your oil....

I thought I read somewhere that Rotella was ditching that formula for compliance reasons? Potential users may want to research it a bit first.

I thought so too.

VALVOLINE VR1 RACING OIL