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?

.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

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.

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.

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.

I have a 74 head all stock in the chambers. It CC'd at 45 with .060 off.

_________________
'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

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