My roller moto 302 in my z28 did a freaky thing...

[Kim_Howie]

Check your fuel pump. I wouldn't have thought that much fuel would go pass the rings.??

[Mr70]

It can if it's in liquid form and an abundance of it too.
I can relate and hope to never revisit that again..

[Big Block 69]

I have had fuel pumps fail & dump gas into crankcase.
Since yours is cracked, you need to change it anyway.

Rick

[Rixls6]

I had a similar thing happen to an engine with a 2-piece intake once.

One of the bolts inside the intake that hold it to the head came loose. When we fired the engine after sitting for a while, the bolt lodged in the intake valve and caused a similar explosion.

Both valve cover gaskets blew out, the oil pan mushroomed out and blew it's gaskets, and both mufflers blew out.

[Kim_Howie]

Rick, If that much fuel gets pass the rings I would say that motor has more problems than gaskets.JMO Most of the time the fuel stays on top of the piston and that is not a good thing on the rods when you try to start it.

[Salvatore]

The motor hydrauliced on gas!

[Kim_Howie]

Not a good thing. My 68 Gibb nova 427.

[ORIGLS6]

My first guess would be the diaphragm in the fuel pump. Since you have to replace it anyway, check the diaphragm when you get the old pump off. If they sit for long periods they can drain down and dry out. Then when you crank them over they try to pump gas but it takes the path of least resistance,.... right into the crankcase.