(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.