Or crap fuel with iron heads. Many many years ago I had just got my 340 out of the motor shop and had a pretty hot tune in it. I was running low on money so I grab the gas can that was in the garage and ported into the fuel tank, about 10 miles down the road I miss the shift and started out in third gear blew out both head gaskets at the same time due to detonation I guess? and they were quality gaskets Mopar performance. I have moved to steel shim gaskets and will never look back! jmo
