My normal sources for parts doesn't offer any gaskets thinner than .039. To get to the quench and DCR I want I need a thinner gasket. Can anyone recommend a good brand ( I typically prefer FelPro) that will do well on the street? I suppose this puts me in steel shim territory, do I need to do anything special when using such gaskets? I'm used to using the FelPro no-retorque blue .041 gaskets and never had a problem but with such a short gasket I suppose things need to me more exact. The block has been decked and we determined that the heads were not in need of surfacing so things are nice and flat.

Is there a .015-.021 head gasket that is a composite instead of just a steel or copper shim?

Rich, how thick are the MLS gaskets used for the newer Vortec engines?

Cometic will make a .027 MLS (think that is the thinnest) for about 80.00 ea. GM still sells the .022 steel shim for MkIV motors that came on these as OE back in the day.

Rich, how thick are the MLS gaskets used for the newer Vortec engines?

I've no idea.

Might want to look into it.

From their website it looks like Cometic only goes as thing as .027. I really need something in the .015-.018 range if I can find it.

Assume this is MkIV motor. Only thing I have come up with are the Steel .022 GM's, Mr Gasket also makes a .021 I think and in MLS, Cometic will go down to .027. Other than copper, that's about it.

The Mr. Gasket steel shim gasket is for series cooling. I've used 'em with good results.

The GM steel shim gasket is set up for parallel cooling. Haven't used 'em, wish I would have known the difference before stocking up on the Mr. Gasket units.

You need to coat the steel shim gaskets with "something" as a sealer. Aluminum paint, CopperCoat, Teflon plumber's paste, whatever. You could probably coat 'em with mucus and be fine.

If a steel shim gasket will seal a 454 LS-6 and keep GM's warranty beancounters happy, it'll probably work fine for anything you'd need. Make sure the gasket surfaces are SMOOTH and FLAT. Torque in stages. You'll be fine.

Ditto Schurkey here!!

I've even used good old, Permatex, "Indianhead Shellac Gasket Cement", on Mr. G's steel shims but they are hard to remove later!!

And one guy used gun grease too!!

pdq67

The Mr. Gasket steel shim gasket is for series cooling. I've used 'em with good results.

The GM steel shim gasket is set up for parallel cooling. Haven't used 'em, wish I would have known the difference before stocking up on the Mr. Gasket units.



Maybe I am missing it, but which are you saying is better for cooling? The Mr. Gasket or GM's?

Thanks!!

http://www.chevelles.com/forums/showthread.php?t=38820&highlight=Parallel+Cooling

Scroll about half-way down.

IF your block has the extra cooling holes in the deck, the parallel-flow gaskets are probably better, but not a big difference. The GM steel shim gaskets are parallel, the Mr Gasket steel shims are series-flow.

I seriously doubt I have a parallel block since it came from a '80's 1 ton truck. However, I will take a look the next time I am in storage.

My heads are Pro-Topline iron pieces, I am curious which way they are cast.

"I seriously doubt I have a parallel block since it came from a '80's 1 ton truck."

'70's tall-decks had parallel cooling, and probably even the LS-6s. No telling what yours are, but parallel would not surprise me at all.



"My heads are Pro-Topline iron pieces, I am curious which way they are cast."

You mean whether they are cast for series or for parallel cooling? First guess: BOTH, like every other BBC head I've seen. The difference is in the BLOCK and the GASKETS.

Either system can be converted to the other. Going from series to parallel may involve drilling a few holes in the decks of the block, and changing to parallel-flow gaskets.

Going from parallel to series involves a head gasket change, but there'd be no point in doing that because the parallel system is slightly "better".

MRG-1131...................this is the part number for mr gasket steel shim heads gaskets , they packaged in pairs and sell for 22 bucks here local.

they measure .018 compressed thickness, i have about 1/2 dozen used ones hanging on the wall. cant seem to throw much away.

use copper coat spray on them let them tack up before putting on the block, torque like normal, then you are done , been running these gaskets for years have had no failures.

Maybe I'm asking the obvious here, but are we talking about how to use steel shims on ALUMINUM heads or is that a complete no-no?

Deleted for now. Too buzzed to think. Sorry.

I don't think you want to run a real steel shim headgasket on an aluminum headed and headed/block engine b/c they will probably brinnell the aluminum in either case.

Fel-pro's rubber-coated, .015" thick steel shims can be ran on aluminum heads if not mistaken b/c the rubber takes care of any brinnelling tendencies.. BUT they are only made for SB's!!!

pdq67

I don't think you want to run a real steel shim headgasket on an aluminum headed and headed/block engine b/c they will probably brinnell the aluminum in either case.

Fel-pro's rubber-coated, .015" thick steel shims can be ran on aluminum heads if not mistaken b/c the rubber takes care of any brinnelling tendencies.. BUT they are only made for SB's!!!

pdq67

I'm involved in exactly that discussion...on another board ( http://www.realoldspower.com/phpBB2/viewtopic.php?t=17690 ) I was...ummm..."under the weather" and thought I was replying to THAT thread when I posted above.

Like pdq67, I was under the impression that steel shim gaskets are a poor choice for aluminum parts. Not everyone believes that, though.

I can tell you that my Trick Flow Twisted Wedge heads needed to be planed after using the Fel-Pro "pre-flattened steel fire ring" composition gaskets that are supposedly "aluminum safe". I had deep circles embossed around each combustion chamber from the fire rings. Not happy about it, either. So, I suppose, how much worse can steel shim gaskets be?

I have the Mr gasket Shim installed on my 71 468 block with good luck so far. Approx .018 to .020. engine deck was in good shape and the heads were fresh. Been on since Oct. 05. I have also heard do not use the shim on Aluminum heads. I think its Mr gasket who says that.