Can someone tell me what my options are for a thin head gasket for a 400 with aluminum heads? Part numbers would be greatly appreciated. Thanks !!

 

I wouldn't go less than .015. Some 305 TBI guys use that thickness when they go with vortec heads. However, some blow them out in no time when their CR's get above 9.6:1.

 

I would not put a thin gasket on an engine with aluminum heads, especially a 400. The center two cylinders are too close together to get a good seal. Deck the block or shave the heads & use a thicker gasket.

 

Both the block and the heads are decked. The deck height is .025 and I was hoping for a .020" head gasket to minimize my quench. I'm about ready to go with the Mr. Gasket Ultraseal set but the compressed height is a whopping .040". Too much for me. I wish I could find something in a .030" without going to the expensive copper shim. I wish I would have zero decked but it's too late now. The shortblock is assembled.

 

i'd run a gasket made for aluminum heads and an iron block and not worry about the thickness. if i found two gaskets that met the aluminum to iron requirement then i'd get the thinnest, if that's what i as after. aluminum to iron causes some problems because of the differant expansion rates. it's not to late to have the block zero decked, you'd just need to start over. other than time there wouldn't really be any extra expense involved except the machin work.