6.7 Block - Is a girdle a necessity?
 

I have been running a 5.9 for several years now over the 1200HP mark and have never had any main bearing trouble. I am starting to collect what I need to venture into the 6.7 world and know nothing about the characteristics of the blocks. Has anyone ran a pulling engine making over 1200HP without a girdle? If so, what kind of RPM and how many runs? My little 5.9 has been turned well over 6000rpms at the line and makes runs anywhere between 4700-5200 down the track depending on the track.

I searched through 3 pages of old posts looking for some info but only found posts talking about a build or stuff for sale.

Looking for some input... Not a bunch of "if your spending the money, why wouldn't you do the girdle too" comments.

Thanks!

I would at that power level and rpm just for insurance

I’d argue that cylinder wall integrity is more of a concern at 1200hp with a factory 6.7 block. There are also many examples of 1200hp engines living with a stock 6.7 girdle, albeit with bigger hardware. The extra displacement is definitely fun!

Truth :rockwoot:

After making the switch from 5.9 to a 6.7. Screw the girdle buy sleeves instead. That much rotating mass at that rpm is bound to hurt those walls.

I’m definitely going to sleeve this motor, but wasn’t sure if anyone has run a 6.7 block without a girdle. The industry makes one believe that the blocks are relatively weak unless they are deck-plated and girdled but is that really the case? I’ve learned over the years that not everything you see is as much a necessity as it is a sales pitch sometimes.

I highly doubt it is necessary. I know fleece has stronger main cap dowels though, so they must have had issues with those.