A buddy had a 67 mustang with a mild 428 ran 12.20s. He put a 250 shot Comp-U-car on it, wow 10.57 3 times n a row, never heard it shift just one loud roar down the track. I raced it a few times using it just in third. I blew the engine after a solenoid stuck while dry hopping behind the line. Engine died so after shutting the bottle off and cranking over for 30 seconds figgered it was cleared. Wrong, pow, bent rod, cracked block and head, blew out the head gasket and jacked the head bolts. Won’t use that stuff again!!