(Possibly) Blew a head gasket looking for suggestions

[M-Sport fan]

Following SP63s requirements:
0-150 miles - Motul 10w-40 break in oil
150-300 miles - conventional 10w-40 (I got castrol, but any decent conventional is fine)
300-500 miles and 500-1000 - conventional again (and again)
1000+ and in perpetuity - Amsoil extended life 100% synthetic 10w-40

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)?

 

[Capri to ST]

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.

 

[arlisscm]

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)?

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....