Just wanted to thank everyone for all the info. Didnt realize how important oil ingredients were !

+2

Mobil is still making 15-50, but it is a race only formula. That is why Wally's is not carrying it anymore. My local distributor has it on hand. It say's race use only on the bottle now. Has higher zinc and phosphorous. Can't use in street vehicles because it will eat up your converter, or at lest that is what the car manufactures say.

Penzoil still makes a 25-50wt racing oil as well that is high in zinc.

castrol full synthedic syntec 20/50 said its made for flat tappet cams has lots of zinc

I used Gibbs Oil in my motors to break them in. My builder said that is what should be used. I figure if he built them and is standing behind them then I will do what he says.

Watch out for 100% ester-based synthetics in boats unless you get your oil temp well over 210 degrees on a regular basis. Accumulated water condensation in esters can create acids.

I did use the Joe Gibbs Break in oil for the first 25 hours. My engine builder likes the Valvoline VV851 20W-50, so that is what I use.

Just an FYI... I was a diehard Valvoline VR-1 20w50 user in all my performance boats... that is until my recent failure in my 575sci. I ended up loosing a cam lobe (flat tappet) and subsequently killed the cam and lifter. I sent the oil out for testing and per Valvoline's website, the zinc count should have been upwards of 1400 and my results came back in at 617. No where near where it needed to be. Mind you this oil had 1.5 hours hours on it as well. So with that said, no more valvoline for me. Once the motors are done, Joe Gibbs for the break-in and then Brad Penn. Even though I won't be running flat tappets anymore, still great oils to run!

I was told by my machinist and my spec and build sheet man Bob Madera to break in on Joe Gibbs and run Bradd Penn all the way. Used to run VR-1. and have heard from one very respected engine builder to just run oil i.e. castrol, valvoline, bradd penn. no full synthetics. all i know is that his engines have been dummy proof and pushing that boat for 3 years now. Bet the bulk of you guys know who he is...