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#1
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I am rebuilding a stock 1973 440 for my wifes Charger this has a comp. ratio of about 8.5. In my garage I found a set of 906 heads. Question is. If I shave the heads about .060 will it bring the comp ratio up to about 9.2.
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#2
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the actual comp. ratio on these L.C. 440s are really around 7.8-8.0 to 1. even milling .060 of the heads & using the steel shim gasket would only bring the comp. ratio to 8.4-8.5 to 1. the best way to bring your comp. up is to use the pistons for the earlier 440. there's .070" difference in compression height between the L.C. & H.C. engines.
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#3
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Thank-you Buddy440, I do realize I have to change my pistons. But I am trying to do this rebuilt as economicaly as possible. I live in Canada and the price of speed parts are astronomical let alone dealer parts. Anyway I have been in the garage all day checking and measureing clearances. The cylinders are exeptible and the pistons are perfect. The previous owner has replace the cast units with forged pieces. So I think I will keep these. My deck height is-.119, which renders my comp. ratio very low. If I deck my block to the same as the old HP. units would I require different push rods. Or is the push rod length the same as the 69-70 blocks as apposed to the 73 blocks.
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#4
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I live in Edmonton,too bad you missed the RedDeer swap meet,yes the push rod are the same lenght.KB pistons should be cheap.
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#5
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if you have a deck of -.119 than the pistons have a better comp. height than the stock cast units.
.119 of deck = 28.5cc of vol. .020 steel shim gasket = 5cc of vol. if you mill your heads to get them down to 79cc s you will get 9.0:1. if you can get 516 of 915 heads this will make things a lot easier. for V8 s ( cubic inches x 2.0483) divided by ( comp. ratio - 1) = combustion area |
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