Detonation on 408 Stroker

Hi, I haven't measured the compression, it's just on the stats the engine builder gave me, so no, I can't be certain.
Here is what he gave me:
4.030 Bore
Piston to Deck .024” (11.5cc) Head Gasket 9cc
Head 69cc
Total 89.5cc
Compression Ratio 10.3:1