LT1 POWR

Are there LTX specific head gaskets?

I'm trying to get my compression ratio figured out and need to know what head gaskets I can use. The heads are at the porter and he needs to know how far to mill the heads.

The pistons are .0185 in the hole, so that leaves me with a compressed head gasket selection of about .016-.021 to get a .035-.040 quench.

Also should the head gasket be bigger than the cylinder bore. Like on a 4.030 bore should I use a 4.060-4.125 gasket. Is there any downsides to using a bigger gasket, other than a little less compression. What about using a 4.030 gasket, any downsides?

Seems like people are using a felpro 1074 gasket, but I need something thinner.

MikeGyver

You can get cometics in any thickness and bore. The cometic gasket for a stock 4" bore has a 4.040" bore. I would keep at least that .020" clearance all the way around your bore, MLS gaskets move around a bit when everything heat cycles. If you go too big, it's not only unnecissary but you loose sealing surface. My bore is 4.031 and I'm just going with 4.1" and a .040" thickness giving a quench of around .045"

LT1 POWR

I found a SCE copper gasket with .021 compressed thickness part number 011062LT.

So a regular SBC head gasket will work then. I didn't know if the coolant passages on LT blocks are different than on SBC blocks.

MikeGyver

I think they're different. Aren't the copper gaskets usually for O-ringed blocks?

jsetzer

Yes all sce copper gaskets require an oring from what their tech told me. Guess who was the dummy that tried to run one without. I had major water sealing issues too, but that may have been related to the compression sealing issues.

I had good luck with MLS, but am considering good old felpro again. Isn't the Impala gasket a little thinner?

LT1 POWR

I can't find a thin enough(.020 range) MLS gasket. The only thin ones I can find are copper.

Do LTX motors need a specific LTX head gasket or will a standard SBC work. Summit didn't seem to know anything and said I'd probably have to have a custom gasket made.

LT1 POWR

Found a Cometic MLS with a .027 compressed thickness so it looks like I'll be ordering that one unless anybody knows of any thinner.

MikeGyver

All Cometics are built to order, they can be made in any thickness. Ask Cometic what the thinnest they can do is. I just ordered my Cometics through byunspeed.com for $75 each and free shipping.