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madman
10-06-2005, 02:06 AM
Just came back from trip north. Hauled three 4 wheelers two trailers loaded and three guys also. My poor 460 ford did ok but more horsepower is required. I blew a headman header on one cylinder. Do aftermarket aluminumn heads run too hot on propane as a fuelé Im curious also how do you seal up a header flange really well. Thanx Madman

speedy
10-06-2005, 07:35 AM
I have used Chesterton nickel compound on the head and header with the gasket, no probs. But it isn`t a 460 http://bbs.homeshopmachinist.net//smile.gif
Used to use black silicon seal on my Triumph header pipes and also to extend the life of the crappy harley header gaskets, no more probs here either. It gets gooey but doesnt blow; it`s worth a shot.
Ken

torker
10-06-2005, 07:48 AM
Madman, I've had one truck on LPG for about 6 years now. A 406 purpose build for LPG. I finally got sick of replacing exhaust components so I switched back to cast iron manifolds and a full stainless steel system. I built my own mufflers with some scrap 5" tubing from a pulp mill. Three years now and no exhaust issues.
I really don't see where alu heads should be a problem with LPG. If it's getting that hot perhaps the mixture is too lean.
For header flanges that are a problem to seal I always use copper exhaust gaskets.
Your topic title says you blew a head gasket. I use copper head gaskets on my race stuff (O ringed block and heads though) and have never had a problem.
Headers for a 460 can be crazy expensive. I'd lean towards stainless. Probably have to make them myself. Or perhaps have a good set of steel tubing headers ceramic coated.
Edit..** DOH ** OK...it doesn't say head gasket!

[This message has been edited by torker (edited 10-06-2005).]

torker
10-06-2005, 08:12 AM
Another thing...what mixer are you running on that 460? If it's just a typical 425 impco that will cost you a lot of power.
There is a guy here who was in partnership with his brother and they made a cast alu intake for Ford 385 series big blocks that held two 425's. They sold a lot of them to tow truck owners on the west coast.
Since then there is a company that builds a 900 cfm mixer that is better for big blocks. I can't find the place right now but will look for it later.
Russ

jamscal
10-06-2005, 09:29 AM
I had problems with the manifolds mating to the aluminum head on my old jag.

Someone recommended the copper gasket spray, and it worked. Used the stock gaskets. The stuff is pretty thick and tacky.

Good luck,

James

ibewgypsie
10-06-2005, 05:11 PM
A, dip copper header gaskets in paint before installing..

B, use white gaskets but soak them in water all night to expand them.

C, cut the flanges between the tubes, only if there is bolts on each side.. like a chevy..

D, get used to replacing header gaskets. Notch ends on gaskets help some.

rsr911
10-07-2005, 01:12 AM
to your question about aluminum heads. They will run cooler than Ci. On race motors Al heads are good for an additional half point in compression ratio using the same fuel.

For headers in addtion to cutting the flanges between tubes, I've found that permatex Ultra Copper RTV actually works pretty well in conjuntion with the gasket.

Another helpful tip is to use ball and socket connectors after the collectors so less bending stress is placed on the headers from the rest of the exhaust.

Installing an H-pipe will also stiffen things up a bit and provide more midrange power.

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-Christian D. Sokolowski