jyro

around 398 at .570

brad penn breakin and then vr1

That should be fine. What's your open pressure at? You want to make sure you run an oil with a lot of zinc in it. I run valvoline VR1 oil in my race engines and haven't flattened a cam yet.

You can also get the lifters with the .012 EDM oiling hole in the face, and that helps a bit for friction and cam life.

The DLC is really a friction modifier. I don't have any personal experience with them myself as the rules I run under don't allow me to DLC coat anything. The tool steel lifters are about 10 grams lighter than a standard performance lifter and are more suited for high RPM applications. The trick to high RPM or high spring pressure applications on flat tappets is to keep the edge of the lifter from digging into the lobe or too much spring pressure during break in. If your rules allow for a roller cam, I would do that all day every day over trying to make a flat tappet work with high pressures/rpm. The tradeoff is that they are a bit more expensive, but you'll pick up power due to lobe design and reduced friction. Long duration and high ramp rates are your friend in a race engine, if you can keep the lifter from "crashing".

Appreciated, but it's already been taken care of.

I have a 174 roots but thanks anyway

dont no what u have but i have a d1 head unit 900