Running old LA style heads on a magnum block

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hemichuck

hemichuck

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I have heard that someone makes a rocker arm for the old style LA heads that oils through the pushrods like the Magnum. I know that almost all hydraulic lifters available these days are the AMC style that will oil through the pushrods but I want to run an Edelbrock LA style head with a little larger combustion chamber on my Magnum stroker block.
 
That approach would be smartest, if you can find it. All I recall is reading of people drilling the Magnum block to access an oil passage that aligns with the LA head passages.
 
Any of the last of the 3.9 or LA engines were like that from what I understand. Oil through lifters, pushrods and rockers with LA heads. I don't know if anybody makes aftermarket stuff or not.
 
From what I understand, drilling the passage on the magnum is kind of tricky and my short block is already assembled.My old 408 had provisions for both setups but it was an early 5.9 Magnum out of a 1993 van.
 
hemichuck said:
I have heard that someone makes a rocker arm for the old style LA heads that oils through the pushrods like the Magnum. I know that almost all hydraulic lifters available these days are the AMC style that will oil through the pushrods but I want to run an Edelbrock LA style head with a little larger combustion chamber on my Magnum stroker block.
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why not just run the edelbrock magnum heads?
 
The problem is I built my 408 with a magnum block and I used the Icon 744 flat top pistons. The compression ratio with these pistons at 62cc is 12.1,68cc is 11.3 and 72cc is 10.8. The Edelbrock magnum heads have a 58cc chamber so I would be pushing around 12.9 and that aint working with pump gas. I have some edelbrock 60179 open chamber heads that are supposed to be 65cc and If I use some really thick head gaskets I might be able to get them down in the 10.8 range. The pistons are not -0- decked but they are not very far down.I will get a measurement today and do some calculating. This thing might end up in a race car before its over!
 
Just picked it up at the machine shop and checked it out.Its zero decked so I'm going to have to rethink a couple of things.Whats the thickest head gasket you can buy?
 
Cometic will make whatever thickness you want.
 
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