I’ve ran 440 blocks for years without concrete or sonic checking them. One 440 block (Stroker) cracked up thru the mains after 275 eight second passes and was found when I tore it down for rebuild. Sometimes you don’t want to know how bad things are. Lol 😂

1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time