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#1
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approximate compression??
about what would the approximate compression be with a 69hp 340 with the stock high compression pistons with r/t magnum style heads that hAve beeen shaved .030 with 2.08 stainless steel valves??
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#2
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would the pistons hit the head,without a much thicker head gasket.080/.100
I think the pistons are around .050 abouve the deck for open chamber heads,I could be wrong. |
#3
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I put closed chamber edelbrock 6077 heads on a 340 block but I could not use the stock 340 pistons. Not enough piston to head clearance. I think we finally wound up with 10.7 static compression using srp pistons after surfacing the block and heads. The pistons were either flush with the deck or slightly below deck. I don't remember. A friend once used stock pistons on a 71 340 with closed chamber heads and did not check the clearance and it was not pretty when he started the engine. The pistons were hitting the head slightly but it was enough to crack several pistons and break the skirts off of them. Check for Clearance!
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#4
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Yeah, stock 340 pistons have about .060" positive deck height. So, the heads must have this area machined into them for clearance. I do not believe there is any way you can use the modern Magnum heads on it.
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#5
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a 69 340 has a small dome across the whole piston, and it is designed to fill the stock x heads big open chamber. Wont work with magnum heads. They are closed chamber. Unless you run a really thick cometic gasket.
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#6
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I have a brand new set of cometic gaskets that are .1 or .12 thick i would have to check to be sure. Let me know if i should check. I bought them for a project and never used them
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#7
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the problem with thicker head gaskets would be lifter pre load and possible longer pushrods unless you mill the heads a lot then compression could be to high for pump gas. sorry but in seems like a catch 22 again.
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#8
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There is only ever one way to check compression ratios...
It involves careful measuring, using a pipette or syringe or similar to get the chamber volume (your chamber, not someone else's) and a lot of calculations. All re-checked over and over of course. |
#9
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sounds too complicated so there goes that random idea lol
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