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After doing so many swaps and builds I thought I got this one down but apparently not.
Everyone seems to reiterate the same thing, that is, LS engines had two flanges on the crank, early 99-00 4.8/6.0 had the longer flange and later 01+ engines had the shorter one. Except I have two engines here sitting on the stand that are neither of those.
Let's first look at what we already know. This is the longer flange crank that came on early 4.8/6.0 trucks.
And this is the shorter flange that requires a spacer when used with older transmissions.
Now this what I have on two of my engines. One is a 2005 Gen 3 LQ4 from a 2500HD Silverado with factory NV4500. The other is a 2012 Gen 4 L76/L77 from a Chevy Caprice with factory 6L80e. What the hell is this supposed to be?
Last edited by Q8y_drifter; 11-11-2019 at 02:45 AM.
I've never messed with the front wheel drive engine but that is what my first thought was but I also thought they didn't have a starter boss on the block. Does the block say 6.0 or 4.8/5.3?
I've never messed with the front wheel drive engine but that is what my first thought was but I also thought they didn't have a starter boss on the block. Does the block say 6.0 or 4.8/5.3?
They're both RWD 6.0's. LQ4 is an iron block, L76 is an aluminum.
Ok, I'm confused, You have three pictures so what did the one with the odd crankshaft come out of ?
I think you missed what I wrote describing each image. This is what I wrote for the third image.
Now this what I have on two of my engines. One is a 2005 Gen 3 LQ4 from a 2500HD Silverado with factory NV4500. The other is a 2012 Gen 4 L76/L77 from a Chevy Caprice with factory 6L80e. What the hell is this supposed to be?
That's a stardard crank flange. The difference is the seal in the rear cover. Take a closer look.
The rear cover is the same part and the seal is seated all the way in both pics. What am I missing here?
EDIT: For further reference I have a third engine (2004 5.7 LS1) also on a stand. It has a crank flange that's flush with the seal exactly like the 2nd pic. What gives???
Is that a crank spacer on the first image or actually part of the crank? The crankshafts in the older motors such as the LQ9's do not require a spacer to attach an older style transmission. I believe the difference is like 0.33 but not 100% positive on that but if you do have the older version crank then you do not need to run the spacer or aftermarket flex plate which has the difference already built into it.
In the end, it's not even the distance from cover face to crank that really matters--it's the depth between the bellhousing mounting flange and the end of the crank. Just run a straightedge between two of the mounting bosses and get a depth measurement. As others have said, though, it just looks like the normal "short" crank with an incorrectly installed rear seal.
11-11-2019, 01:50 AM
Crank flanges and spacers 
