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Discussion Starter · #1 ·
will it fit. I see another post pic and a stock bell is bolted to a 5.3 LS.... but it appears 2 bolts are not installed.
 

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That would be correct. The LS engine has only 5 bolt holes for the bellhousing not 6 or sometimes 7 like traditional engines.

The other situation is that the relationship between the crank flange and the bellhousing mounting surface is not the same as a traditional engine, and you must deal with that too. And some 6.0L LS engines are different from the rest.
 

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Rick is right for the most part, little clarifications.

The LS Gen III/IV motors have 6 bolt holes. Unlike the SBC the very upper bolt is cast and drilled and used un like the SBC. The upper R/H bolt if looking at flywheel is undrilled and not used on the LS. It can not be drilled or you will hit the cylinder.

So the Gen III/IV trans use the upper most hole. All Gen I or Gen II engines don't have that upper hole even cast in their transmissions. So if using an early trans up end up with only 5 bolts in it which is plenty.

The crank offset of the Gen III/IV motors is .400 intoward the crank. So to make up for this to run Gen I/II trans in some applications like the NV3500/4500 and 4l80's GM used a long thick flanged crank for some very early motors. Later around 2000 GM went to a common crank spacing and used with a dedicated flywheel with correct spacing or a spacer for the 4l80 trans applications.

And SBC pattern will work with an LS motor.

Now the LS4 is unique as it was a front wheel transverse mounted motor which has a 60* V6 bellhouse and is the only LS motor built like that. It lacks provision for a starter mount pad so it is a very poor choice for swaps.
 

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Well I learned something. I was unaware that the top hole was there on an LS block.

But if it's not there on the bellhousing, well you can't use it anyway.

It's not a big deal unless some are loose, and that applies to any combo.
 

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Yeah you can tell the later 4l60/80e's very easily as they have all holes cast in the bellhouse (7 total) and the early 4l60/80s don't have the top one even cast (6).

And surprisingly most of the high HP units running the early trans are fine with the 5 bolts. So yeah not that big of a deal.
 

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Yeah you can tell the later 4l60/80e's very easily as they have all holes cast in the bellhouse (7 total) and the early 4l60/80s don't have the top one even cast (6).

And surprisingly most of the high HP units running the early trans are fine with the 5 bolts. So yeah not that big of a deal.
 
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