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#26 |
Registered User
Join Date: Nov 2006
Location: Beaverton, OR
Posts: 49
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Re: "New" '86 C20 need advice...
by granny tranny I assume you mean a 4sp with a granny low and no overdrive, correct?
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#27 | |
Registered User
Join Date: Feb 2005
Location: Alberta
Posts: 248
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Re: "New" '86 C20 need advice...
Quote:
But from the graph I have printed out a 700r4 with 4/10 gears and 33" tires at 65mph your motor is only turning 1900rpms which is to low. My th350 is turning 2700rpm with same 33" tires <that actually measure 31" mounted and under the load of my truck and same 4/10 gear ratio. I haul horses and this combo. It works great for me but if my truck was even a bit lower spead that would be even better. Really what I should have is a Gear Venders overdrive. With the 308 gears the truck sucked gas and had no power. |
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#28 |
Registered User
Join Date: Feb 2005
Location: Alberta
Posts: 248
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Re: "New" '86 C20 need advice...
If I was you I would start looking around for a good deal on a second hand Corporate 14 bolt FF 10.5" ring gear with 456 gears. Your probable only going to be able to find one with 4/10s but thats better than what you have. Those axles sell pretty cheap<think $150-$200> and seals and bearings dont cost that much.
This would give you more bang for the buck than modifying your motor. |
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#29 |
Right turn Clyde
Join Date: Nov 2002
Location: Cincinnati, Ohio
Posts: 2,911
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Re: "New" '86 C20 need advice...
Here is for the speedometer gear calculator.
http://www.tciauto.com/Products/Tech...eedo_gears.asp Here is a tire size calculator. http://www.miata.net/garage/tirecalc.html Here is another link to check out. http://www.ringpinion.com/Calc_RPM.aspx I think 4.10s would be fine for the 3/4 ton. Unless you find a 14 bolt ff that has 4.56 gears. The 3.73 4.10 gear ratios are pretty common. Having the 700r4 is going to get you off the line a little better vs other automatics. I would think about running an external transmission oil cooler. It will help keep the some of the heat build up and stress of towing down.
__________________
1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI |
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