Main cap girdles re-discussed

Read this... https://www.hughesengines.com/TechArticles/2mainbearingstudgirdles04232007.php

Looks like if you're gonna be pushing 600+ HP a main girdle and studs is a good idea but 4-bolt main caps won't do much of anything whether the extra outer bolts are used or not.

crackedback said

600hp, waste of money and time putting a girdle on a SB mopar.

SB ford OEM blocks were NEVER designed for 1000hp and cut themselves in half no matter what bandaid is put on them. Try that 1000hp with a production based mopar, get the same results, broken blocks. Only a matter of time.

Girdles on a SB mopar do nothing to stop the issues of the block breaking or cap walk.

Want peace of mind, buy a better block if you can find one.

Click to expand...

Do they really not work though? When the engine is running each cap gets side-loaded individually so having them tied together allows the other 4 to support each cap as it gets hit with loading from the crank. That's my theoretical view on it anyway. The Jeep 4.0L I-6 got a main cap girdle added in to reduce NVH and works much the same as an SB Mopar one, granted it's not for strength but if it didn't work to distribute the side-loading between the main caps the Chrysler engineers wouldn't have bothered.