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402 on a budget Is my DCR to high?

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Old Dec 6, 2007 | 04:44 PM
  #1  
ufsnola's Avatar
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Default 402 on a budget Is my DCR to high?

I'm tring to use some existing parts on hand to get my motor up and running, but if I plugged the numbers in right my DCR would be 8.9.
Can someone check my figures?
Setup is:
Iron 402
6.2" Rods
10.4 dish pistons
FMS F-13 112 +4
AS 5.3 Heads
.04 4.03 Head Gasket

Absolute Speed 5.3 heads flow:
Lift: intake exhaust
200 141 114
300 202 158
400 255 197
500 293 214
600 313 227

Quick and Dirty Cam/SCR/DCR Calculator Spreadsheet
0.006 0.050 0.200
Intake Duration - ID 280 230 151
Exhaust Duration - ED 284 232 150
Lobe Center Angle - LCA 112 112 112
Intake Centerline - ICL 108 108 108

Intake Valve opens - IVO 32 7 -32.5
Intake Valve closes - IVC 68 43 3.5
Exhaust Valve Opens - EVO 78 52 11
Exhaust Valve Closes - EVC 26 0 -41
Exhaust Centerline - ECL 116 116 116
Overlap 58 7 -73.5

Bore 4
ST = Stroke 4
RL = Rod Length 6.2
Number of cylinders 8
Deck Height -0.008
Piston Dome or Dish (- for a dome + for a dish) 10.4
Compressed Head gasket thickness 0.04
Cylinder Head Chamber Volume 62

Displacement 402.1238784
Static Compression Ratio 11.4280051 :1
Dynamic Compresion Ratio 8.90709173 :1

Just trying to use these parts until I can save up for some heads and a bigger cam. Will this even run on 93 octane? I've seen posts about 8.5 being the sweet spot.

Also I know throwing miscellaneous parts together is not ideal. I'm not looking to break any dyno records here just get the motor running.

Any help greatly appreciated.
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Old Dec 6, 2007 | 06:24 PM
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if you get the tune right youll be fine i say. take the "calculator with a grain of salt. not all those measurements can be exact. when i did mine i did -.008 but when i built it, the truth was it was more like .002.

so 8.9 is doable with a great tune do it.
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Old Dec 6, 2007 | 06:41 PM
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5.3LJimmy's Avatar
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^^^ I agree. Your aftermarket pistons will probably sit more around 0 deck and actual DCR will be slightly lower than calculated. I say let it eat and good luck. For the record I used a different calculator and came up with 8.89 so you are right on.
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Old Dec 7, 2007 | 08:04 AM
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ufsnola's Avatar
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I'm going to get the motor on the stand this weekend and check just where the pistons actually sit.

5.3LJimmy you live right by NoProblem?
As soon as it cools off I'm going to go make a few passes in my TBSS out there...
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Old Dec 7, 2007 | 08:09 AM
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Yeap. I live on hwy 996(same as NPR) about 4 miles from the track.
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