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| Milled Head https://slantsix.org/forum/viewtopic.php?t=52879 |
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| Author: | 63dartdude [ Sun Jul 28, 2013 6:25 pm ] |
| Post subject: | Milled Head |
Just wondering. I know since I have owned the car, that the head has been milled .93. However, I have no idea what was milled before I got the head. But if we assume it is about .95 or so, what would the approximate compression ratio be on that? Could it be 9.5:1 or higher? |
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| Author: | DusterIdiot [ Sun Jul 28, 2013 6:30 pm ] |
| Post subject: | Insufficient data... |
.093 cut doesn't give us a real starting point... How far are the pistons in the bore at TDC? Shim or Composite head gasket. What year head? (If it's a 1963 head, a .100 cut might just put you at 8.2:1 if it started with a 68cc chamber...) Stock bores right/no overbore? -D.Idiot |
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| Author: | 63dartdude [ Mon Jul 29, 2013 4:54 am ] |
| Post subject: | |
The pistons are bored .040 over. I haven't pulled off the head yet, to get that measurement inside the cylinder wall. I am not exactly sure what year head I have on there, but I do know it is not a 63. As I went to get a new water temp sensor, the new one I got was too large. I had to ask for a 71 model truck to get the one I needed. But what it actually came out of, I have no real clue. But I do know the last time I had the head milled, the guy told me it might be the last. He thought it was getting too close to not getting milled again. I have this rattle, and decided just to pull the engine, and take care of all the leaks (oil pan, rear main seal, front tranny seal). Once I get that engine out, I can give better data. Thanks. |
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| Author: | 63dartdude [ Mon Sep 02, 2013 7:06 pm ] |
| Post subject: | |
http://www.foundationpc.com/press/press66d.html Anybody knows about Dick Maxwell. He wrote up that press thing, and according to him, .090 changes it 8 to 9.5. I have a head from 67-74, and I believe it started at 8.4 to 1. Meaning I could be in between 9.5 to 10. But you know you can't believe everything on the net. But he had Staff Engineer next to his name. |
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| Author: | Rug_Trucker [ Tue Sep 03, 2013 4:40 pm ] |
| Post subject: | |
Quote: http://www.foundationpc.com/press/press66d.html
Lots of variables as deck height comes into play. I wonder if a 198 VS a 225 VS 170 would vary? I didn't measure my pistons down in the hole. I took .090 off my head. Polished and unshrouded with stock valves.Anybody knows about Dick Maxwell. He wrote up that press thing, and according to him, .090 changes it 8 to 9.5. I have a head from 67-74, and I believe it started at 8.4 to 1. Meaning I could be in between 9.5 to 10. But you know you can't believe everything on the net. But he had Staff Engineer next to his name. I have a 74 head all stock in the chambers. It CC'd at 45 with .060 off. |
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| Author: | Doc [ Tue Sep 03, 2013 5:16 pm ] |
| Post subject: | |
Quote: ... I wonder if a 198 VS a 225 VS 170 would vary?
Deck height is different for all 3 engine sizes and vary a lot...Example: I have checked many 225's and seen decks at -.140 and up to -.210, as well as in-between. (-.180 is pretty common) In the end... take your measurments and "do the math" to get the DCR number you want. (target 8.0 DCR for regular pump gas) DD |
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