BillyTz06

I'm thinking about using Felpro 1094 steel shim .015 thick head gaskets to up my compression ratio. Has any one used these? Are there any issues with using a thin gasket like this? What gasket adhesive should I use if any? I don't need problems down the road so I need to know what I'm getting into here. Thanks

BillyTz06

BTW, this is a 350 engine w/ 70cc alum heads.

Scott Marzahl

Dont use sealant with that gasket, it is Viton rubber coated. Make sure your block decks and heads are straight. Use a good sealant on your head bolts.

BillyTz06

Thanks Scott, Any negatives with using this gasket?

Scott Marzahl

None that I am aware off, it is listed in the catalog as OK for use with Aluminum heads too. Is your block decked or at standard height?

Ironcross

I believe you can still buy a steel shim OE gasket at the dealers..

BillyTz06

I have a brand new gmpp shortblock and brand new edelbrock performer rpm heads. Nothing has been touched, they are as bought. The thinest gm gasket I found was .028. Do you know of another?

Scott Marzahl

I don't believe GM makes a thin headgasket good for aluminum heads. The one they list for their ZZ4 Al heads is .051". The viton coated Fel Pro will not cause brinneling like a plain steel gasket can.

Manuel Azevedo

Yes these will work for you. But you have the engine apart now, I would consider cutting the heads to achieve the chamber size you want and then you can use a better head gasket, while the shim gaskets work they tend to imprint into head and make it tough to pull the heads later and just put new gaskets on again, but then maybe you'll never need to pull the heads again Just a consideration you can usually go about .060 without having alignment problems which is good for about one full point in compression. But check everything no matter which way you go.

scottyp99

Does the short block have flat top pistons? And what is the deck height? With flat tops, you can take advantage of quench by keeping it between .035" and .045" (deck height + compressed gasket thickness). Something to think about.


Scott

7T1vette

Doing all that work to boost compression a 'smidgen' is pretty much a waste of time. Now, if you were doing other things to increase performance that required you to remove the heads anyway, that would be a good thing. To do only that will be an exercise in futility and you will be disappointed in the results (if any). {just trying to save you some grief}

Indiancreek

7t1vette has well stated the result. If I were to build a small block and wanted a specific ratio I wouldn't do the small changes to get there. I wouldn't start by milling the heads as you affect the intake head contact.
I'd get set on the heads I wanted to use, the stroke, bore, the gasket I wanted to use, and the deck height and send that information to weisco or JE or other good piston co. and tell them what ratio I wanted to end up with and they will provide you with some great pistons. Keep in mind they are proud of them though.. At least you know what you'll end up with.

larrywalk

You will be fine with the Felpro 1094 steel shim .015 thick head gasket.
Since normal deck height of the stock GM short blocks is .025", your quench height works out to be .025" + .015" = .040" which is perfect.

I've used that Fel Pro steel shim gasket and like it!

bashcraft

Sounds to me like the heads haven't been installed yet.

BillyTz06

That's right , the heads have not been installed. Everything is brand new, still in the boxs. It sounds like the 1094 gaskets will work fine and will reach my objective. One more question .... do you need to retorque the heads using the 1094 gasket?

Manuel Azevedo

Yes you should re torque a shim gasket as well as the aluminum heads.
If these heads are still in the box why not send them back and get the chamber size you need, that way you get to use the better gaskets also. just a thought.

larrywalk

Best advice is to follow the instructions of the gasket manufacturer.

BillyTz06

I ordered the 1094 gasket set today. That will give me my targeted CR

Scott Marzahl

Good quench and your target SCR, great job.

MotorHead

Federal Mogul makes or used to make a nice thin steel shim head gasket. You spray it with aluminum paint prior to install. I made 300HP at the rear wheels with that gasket in there and never had a problem with in it in my warmed over "L48"