TransAm-Z

iTrader: (39)

Apparently I didn't do a good enough job picking out my head gaskets for my 408 turbo build. I was getting ready to put my heads on tonight and saw that the LS7 head gasket cooling holes are not lining up with the block.

Does anyone know if there is a GM head gasket meant for the Iron 6.0L blocks that have the following specs? (Or do I need to buy cometic gaskets?)

Compressed thickness (.051")
Gasket Bore (4.125")
Boost friendly (15psi)

TransAm-Z

iTrader: (39)

Any thoughts on modifing the head gaskets? I could drill a new hole that is moved over slightly that will clear the block. Anyone think this would be a bad idea?

Thanks
Jeff

Shawn @ VA Speed

iTrader: (3)

cometic-you can't use gen 4 gaskets on gen 3 blocks-the coolant jacket is different in the block.

TransAm-Z

iTrader: (39)

Isn't the LY6 considered a gen IV block? It appears the only thing not lining up are the vent holes as shown.

Beau@SDPC

iTrader: (14)

The LS7 heads do have different coolant passages, this is why they should always be matched up.

You must use a cometic gasket.

TransAm-Z

iTrader: (39)

Does anyone know if this part number will work with the LY6 block? #C5317-051 The head gasket that cam off the motor was the 5 layer GM #12610046 which is listed for LS3, L76, L92 engines and cometic lists their gasket for LS1/LS6 5.7L & LS2 6.0L.

Also do the cometic gaskets require copper spray to properly seal the water passages?

Thanks

rednari

The correct way of course is to use the right gasket. But, after looking at the pics, the hole line up is a cooling system issue and not the cylinder bore seal. As long as the gasket has the right dimension for the cylinder bore and head bolts, a little trimming to fit the water passage should be OK.

Give it a try and see what happens. I do not see the water seeping out of the trimmed gasket and into the cylinders or leaking into the oil.

Beau@SDPC

iTrader: (14)

For any engine other than an ls7 or lsx, the standard cometic gaskets will work in your respective bore sizes. We commonly use the gm L92 gasket interchangeably on the 6.0l blocks as you HAVE to get a gasket that fits the block but also the head. There is a problem with using a 4.030 or even a gasket smaller than a 4.060 on the l92 head even if its on the iron block. We always recommend at least a gasket that is 4.085 or larger for that.

69LT1Bird

iTrader: (1)

That right there is some crappy advice.

69LT1Bird

iTrader: (1)

Not if the block and head are machined and prepped correctly.

TransAm-Z

iTrader: (39)

Ended up going with the Cometic gaskets! Only one of the small cooling holes is partially blocked. When you really think about it... What's $150 on a $8K motor... LOL

rem308winvtr

iTrader: (24)

the trick flow gaskets work also