It’s just the math that looks attractive.
“Hot Rodders” & racers tend to like a combined 1st gear ratio of 10:1.
While off hand the trucks 833OD is something I can’t remember at the moment, we’ll use a 3.00 first gear ratio for the math.
Now the math;
3.00X3.55=10.65
3.23X3.23=10.433
3.00X2.97=8.91
10.65 being a little overboard. I can live with that. Getting a lower numerical ratio has an effect while in OD. More on that later, below.
2nd & 3rd or normal ratios for the year(s) of the era. Which I can’t recall at the moment.
Overdrive for the truck transmission I have is .71, a slight difference from other OD 833’s. Minor but worth the calculation.
3.55X.71=2.521
3.23X.71=2.293
2.97X.71=2.109
As you can see, a 2.52 final drive ratio is just fine for the interstate Hwy. going lower than a 3.55 with the 27.5” tires will have the engine turning very low. Great to a degree. Sipping gas slower than a camel goes through water is an awesome thing.
Not what I’m after. A small cam will be added to the 5.9. Howard’s Hyd, 220@050 On a 108 w/.540 lift.
While many point to the big drop as a “Problem”, I’d agree it’s not what you want for any type of racing, mild or otherwise all out.
What it is I’m after is a little better get up and go from the stop and the ability to cruise the Hwy at a reasonable rpm at speed.
The “BIG” drop from 1st to 2nd is something I’m very familiar with as I had a 318 Duster with 3.23’s and the 3spd transmission that also had the low first gear. For me, it is NOT a big thing to produce the extra rpm’s to make a second gear change into a good useful range.
My tires? I looked inside the door jamb to see what the OEM spec tire was. It said FR-78. After some Internet searching around on the various tire sizes available and the diameter of the FR-78, the closest tire I could find to the listed diameter was a 275/60/15.
Now with a gain of salt of what the Internet listed as the tire diameter and what’s available to match, I ended up with Cooper Cobras front and rear. Fronts being slightly different at 235/70/25, a slight bit smaller.
The real thing YOUR after is speedometer readings.
All readings if not dead on are within 1-1-1/2 mph, speed dependent.
This was measured against the phones gps and local traffic speed alert signs.
The revised cluster contains Autometer Z series gauges.
This car is an electrical disaster FWIW.
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