(Possibly) Blew a head gasket looking for suggestions

Did SP63 purposely build it with clearances to handle a 10W-40 oil, or is that what they suggest anticipating the proposed cylinder pressures with your setup under increased boost and an aggressive tune (or some combo of the two)?

I was also wondering why you're using 10W-40 oil.

10W-40 is the requirement from SP63 as that is what the bearing clearances are set up for.

As you mentioned, my guess would be it is for higher load capacity to handle higher cylinder pressures, bearing loads, etc.

Since the engine durability is rated for 550-600HP, it is built with a lot more stress in mind than what it is going to see. For now....

Using my commute to contribute to the break in miles (only ~36 miles a day, but adding extra by just driving around more on my way home), looking to hit the 500 mark tomorrow to do oil change #3. Then get to the full 1K by the end of the weekend to get it all done and sorted. Dyno/tuning session still scheduled for May 11th as of right now.

Scope of the rebuild continues to creep, just pulled the trigger on a Paragon/Alcon front BBK to replace my Wilwood setup. Wilwood setup has worked fine, I just go through pads/rotors so fast, so I want something more track focused and beefy to hopefully get more time out of the consumables. Lead time is 4 weeks, so I may or may not have them on for my first set of track days May 30 and 31. Ordered a new set of front pads for the Wilwoods just in case the new setup hasn't arrived yet.

500 mile mark achieved, oil change #3 complete.

Nothing on the magnet, nothing in the filter, and a few stray bits of glitter in the pan. I cleaned the pan fairly well before hand, but who knows, was a dozen or so little bits in there. I'm not overly concerned.

Kind of seems like the “glitter” has decreased with each change. Have you mentioned this to the engine builder? Hopefully you stop seeing it all together soon

Yeah, mentioned it to SP63, all normal stuff. Should be doing the 1,000 mile change this evening. I'll give the pan a more thorough clean to eliminate residual glitter. But there are all sorts of places for it to hang up, so it probably won't stop completely for a few thousand miles.

1,000 mile oil change done yesterday evening. Once again, clean plug, clean filter, and a few stray flecks of glitter hanging out. Cleaned the pan pretty well this go around, hit it with brake clean until I started contemplating the vastness of the universe and smelling colors, so the glitter should only be the new stuff. But, there was a very small amount and it was hard to get on camera. (I tilted the pan to get it all in one spot)

Break in is "done", going to keep driving it throughout the week, then onto the dyno for tuning next Monday.