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Compression Height - AMC Pistons

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Cj-360 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Cj-360 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/21/2008 at 7:59am
You know CompCams didn't suggest any specific C/R.
And re carb. it's a 470 cfm truck avenger not 670.
 
Now, I'm sure I cannot find thos con.rods of 390 here in Iran, but instead I'll have to order the pistons. But as you mentioned the compression height is 1.570 so, what would that give me? C/r? I'm sorry, but I'm a poor c/r calculator.
 
Does that do me any good? the EGGE pistons?
Or shall I just shave the block?
Or should I just put the edelbrock heads on and it'll be better?
Because I don't have more than 5,000 miles on the engine it's too much to take everthing off to shave it.
I'm confused, pls advise me.
 
Thanks,
Houman
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PHAT69AMX View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2008 at 1:56pm
Posted a reply in the other thread.
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redrebel View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote redrebel Quote  Post ReplyReply Direct Link To This Post Posted: Sep/13/2017 at 7:31pm
Comp. ratio help
70 390 030 over
048 head gaskets
72 401 crank
K1 401 rods
Wiseco 030 9.5:1 pistons
runs great 
Thanks in advance 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote redrebel Quote  Post ReplyReply Direct Link To This Post Posted: Sep/13/2017 at 7:34pm
sorry typo 040 head gaskets
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Sep/13/2017 at 8:56pm
Wiseco also does a forged piston for the 360 with 21cc dish that would bump up compression but will obviously cost more. You can also get a gain by running a thinner Cometic head gasket that can be ordered in any thickness down to 0.027", assuming you don't mill the block for zero deck clearance and still have the pistons down the hole at least 0.010" or so.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote redrebel Quote  Post ReplyReply Direct Link To This Post Posted: Sep/13/2017 at 9:02pm
Motor is done and in the car runs good just want to make sure I got a good idea what the compression ratio is thanks
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Post Options Post Options   Thanks (0) Thanks(0)   Quote redrebel Quote  Post ReplyReply Direct Link To This Post Posted: Sep/13/2017 at 9:14pm
Motor is done and in the car runs good just want to make sure I got a good idea what the compression ratio is thanks
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PHAT69AMX View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: Sep/13/2017 at 10:37pm
CR Calc Requires ALL these Values:

x.xxx" Block Bore
x.xxx" Crank Stroke
x.xxx" Block Deck Ht
x.xxx" Con Rod Length CtoC
x.xxx" Piston Comp Ht
x.xxx" Deck Clearance, +=In-Hole
xx.xx  cc's Piston Dish Volume
xx.xx  cc's Cyl Head Comb Chamber Volume
x.xxx" Head Gasket Thk
x.xxx" Head Gasket Dia

Note: All values used are Nominal, have manufacturing variations,
      and should be confirmed from actual parts for actual Values.

Note: DYNAMIC EFFECTIVE COMPRESSION RATIO is .......
      The 1st & "MAIN" GOAL and "DESIGN FACTOR" or whatever...
      Somewhere between 8.5 & 9.0 to 1 DYNAMIC CR is the GOAL...

1st Determing "choice" is .... THE CAMSHAFT.....

CAM INTAKE VALVE CLOSING ANGLE "DRIVES" EVERYTHING ELSE
relative to ALL Other PART SELECTION and MACHINinG WORK

Cam Intake Valve Closing Angle determines Dynamic CR
that results from the combination of ALL the other parts.

Maximum Dynamic Effective Compression Ratio
Maximizes HP & Torque.... on PUMP GAS !

Pick a TOP SPEED in MPH, this yields Feet per Minute.
Pick the REAR TIRES, this yields TIRE RPM.
Pick a REAR GEAR and Trans Final Drive Ratio,
this determines DRIVESHAFT RPM....
Pick a Max Engine RPM, this Determines the CAMSHAFT.
Now from the CAM, pick all other MOTOR PARTS to get
8.5 to 9.0 to 1 Dynamic Effective Compression Ratio.

All nothing more than the opinions of one man.
Not worth the paper they're printed on.....
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