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6 Inch Connecting Rods

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Old Jun 19, 2008 | 01:30 PM
  #1  
1989GTATransAm's Avatar
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
6 Inch Connecting Rods

I'm posting this for general information. On researching my new short block I have found out that when going to a 6 inch rod the total piston/rod weight is reduced. The will aid in the balancing of your motor and the force applied to the crankshaft at higher rpms.

Also something else I did not know. I was playing with my dynamic compression ratio calculator and with the 6 inch rod at least in my case it lowers the DCR slightly. In my case that is a good thing.

I'm shooting for a static compression ratio of 11.00:1 and a DCR of 8.5:1. Well with the 6 inch rod it brought in the DCR right at 8.51:1 with my target 11.00:1 compression ratio. With the 5.7 inch rod the DCR was a little higher at 8.55:1.

Also the rod angle is a little better with the 6 inch rod. Funny on the horsepower. With DynoSim it says I will gain 2 horsepower. However with PipeMax it says I will loose two horsepower. I'll just call it even.
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Old Jun 19, 2008 | 03:49 PM
  #2  
Sonix's Avatar
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
Re: 6 Inch Connecting Rods

haha, that's pretty standard results when going to a 6" rod. (re: research)

Teeny tiny changes on paper. The actual real world results, well, I think the jury is still out on that. It's such a small difference, I think density altitude, cloud cover, and lunar cycle will have more noticeable effects
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Old Jun 20, 2008 | 02:19 AM
  #3  
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From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: 6 Inch Connecting Rods

Allen still thinks he's building a race car engine in a street car body. You'll never be happy Allen, so just go with the 420ci aluminum small block engine.
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Old Jun 20, 2008 | 08:32 AM
  #4  
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From: Southern IL
Car: 88 GTA "Cocaine"
Engine: 350 tpi
Transmission: 700r4
Axle/Gears: 3.27
Re: 6 Inch Connecting Rods

longer rod or stroke= slower reving engine

thats why the 302 that came in the 68 & 9 camaros were so bad ****
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Old Jun 20, 2008 | 11:42 AM
  #5  
1989GTATransAm's Avatar
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Re: 6 Inch Connecting Rods

Hey, just taking advantage of the new technology. How did I know my car with TPI would want to rev and make good power into the high 6000rpm range.
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Old Jun 20, 2008 | 11:48 AM
  #6  
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From: Bedford Tx
Car: 1991 Z28 1LE
Engine: 370CID GenIII
Transmission: 4l60e
Axle/Gears: 4.33 Moser 9inch
Re: 6 Inch Connecting Rods

Originally Posted by jamon8
longer rod or stroke= slower reving engine

thats why the 302 that came in the 68 & 9 camaros were so bad ****
rod length doesnt effect stroke.
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