Project 6-71 340 Demon

Blownfish said

Sorry to say, but there is no such thing.

And 8 pounds of boost out of a 671 on a 340 is a lot, you definitely need a good girdle or 4 bolt main caps installed. You also need to make sure that your final compression isn't too high with that much boost.

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I disagree. That block will take 8PSI Easily without any 4 Bolt caps. If the 4bolt caps are Aftermarket it will actually weaken the block in those areas when you drill for them. A Girdle is also a Myth though it may make you feel better, it does almost nothing on a SBM. Most of the big engine builders "YES even the ones on this site" do not drill their blocks for 4 bolt mains or use a girdle on their radical small block builds.

I know of a guy that built a SBM with over 20psi, stock block & Crank that wound it up to over 7K and made over 900HP at the wheels. It lived no problem for a very long time. It is all in the tune.

Use studs on the mains. Studs on the heads with Cometic gaskets and you will be good to go. If you get worried about Detonation throw a Meth Injection kit on it. That blower would probably love some cool mist sprayed through it!:D