Blocking exhaust crossover on cast-iron heads

[Rob R]

Furnace cement?
Hydraulic cement?
What is the best material to use to block the exhaust heat crossovers On Chevy cast-iron heads?

[enigma57]

Rob many moons ago, we used to melt down old pistons and pour the molten aluminum in there to block these passages. Not sure what folks use for this now of days.

Hope this helps,

Harry

[BigBro74]

Fel pro 1204 gasket has stainless plates that block this - they work great—no holes- already installed in The gasket

[mag2555]

Cotronics in NY sells a ciramic epoxy that will more then handle Exh temps.
I used use it to block crossovers since I can shape it like the other ports and gain back the lost flow that you still have by just using a block off plate type gasket!

[pdq67]

Rob many moons ago, we used to melt down old pistons and pour the molten aluminum in there to block these passages. Not sure what folks use for this now of days.

Hope this helps,

Harry

I have read where guys used to fill flathead blocks this way back years ago.

Way before my time..

pdq67

[Bob Hollinshead]

I filled some on a pair of BBC heads with melted aluminum and it wasn't difficult, made a steel sheetmetal dam and wedged it in the valve pocket, melted some aluminum scrap in a steel container with a Oxy/acetylene torch and poured it in.

[Bob Hollinshead]

https://www.facebook.com/photo?fbid=102 ... 8247909678 Scroll through the pics

[Walter R. Malik]

Furnace cement?
Hydraulic cement?
What is the best material to use to block the exhaust heat crossovers On Chevy cast-iron heads?

Molten Aluminum

[MadBill]

Hard-packed wads of aluminum foil.

[PackardV8]

Cotronics in NY sells a ciramic epoxy that will more then handle Exh temps.
I used use it to block crossovers since I can shape it like the other ports and gain back the lost flow that you still have by just using a block off plate type gasket!

Anyone ever done before-and-after on the flow bench or dyno to quantify this?

[gmrocket]

Like most others have said, melted aluminum.

i made a small ladle out of 1/4" plate the in shape of a triangle with a li and 3 foot handle so its easy to pour when molten...a torch under it with lid closed,,20 minuntes later its ready . not very big, about 4" along each side and 4" high. never had the aluminum come loose in the head.

i get the head warmed up a bit too so it doent pop and splash when dumped in

[F-BIRD'88]

Hard-packed wads of aluminum foil.

The thick stuff aluminum catering baking pans etc

[1980RS]

I wonder if one could use that Alumalloy stuff and melt that down in there. Would be pretty cheap and easy.

[Walter R. Malik]

I wonder if one could use that Alumalloy stuff and melt that down in there. Would be pretty cheap and easy.

I use a small hand held crucible and melt old piston skirts I have knocked-off.

[bigmike]

Fel pro 1204 gasket has stainless plates that block this - they work great—no holes- already installed in The gasket

I used them a couple times years ago they always seem to burn holes in them after a while on street/strip engines for me. Anyone else see this?