That’s why my B1 heads are on a Keith Black block. I would never put B1 heads on a stock block as that is a ticking time bomb. My buddy Tom Hemphill in Pa builds so powerful engines and I’ve seen him try every bandaid known to man and they still crack. My last stock block build made 275 (8.60) passes before I found a 3 inch crack. And that was with 440-1 heads before I really leaned on the porting work. They will be getting a 2.225 intake valve and then on a mega block I have here.