RHamill
Ryan
I didn't know you can drive 0 mph
I skimmed through this whole thread twice, but it seems you have a 98 chassis, if it was a rolling chassis at the time you got it, the gears possible could be different, you can figure out what gears you have by jacking up the rear of your truck, put it in neutral, spin one of the tires forward (spin it left if on drivers side rear, right if on passenger side rear) I'll type out the procedures as following..
1. Like I said before, jack up the rear of your truck by the rear axle, I don't like using the axle tubes, I prefer the diff case.
2. Crawl under the truck and mark a horizontal line about two inches long on the drive shaft with a piece of chalk, bright sharpie, or something.. when I say horizontal, I mean it should be parallel with the shaft itself, so draw the line on the shaft, and try to remember where it started, just spin the wheel until the line is facing right at you..
3. Now you can determine your gear ratio, which is the number of drive shaft revolutions that were made in relation to one tire revolution. For example, if your drive shaft rotated three and ~3/4 times in relation to one tire revolution, your gear ratio is 3.73s, if it rotated 4 and 1/10th times, then that's 4.10s, you probably half 3.42s or 3.73s.
So the gear ratio is the relation of your pinion gear to ring gear.
So in laymans terms, if someone had 3.42s and 265/75r16's, their gas mileage would be pretty good even for a TBI 350, but if that same person swapped out the 265s for 305/70R16s, and left the 3.42s, that would be hard on the truck and kill gas mileage, or if that person swapped out the 3.42s with 4.10s with 265s, those smaller tires would be spinning a lot more, and thus the truck would be a lot quicker off the line. But if you swapped out original 265s and 3.73s on my truck and put in 4.10s and 35s, it would compensate the larger tire for the lower gears, so gas mileage and speed would be about the same as stock, that's why people swap gears.
I skimmed through this whole thread twice, but it seems you have a 98 chassis, if it was a rolling chassis at the time you got it, the gears possible could be different, you can figure out what gears you have by jacking up the rear of your truck, put it in neutral, spin one of the tires forward (spin it left if on drivers side rear, right if on passenger side rear) I'll type out the procedures as following..
1. Like I said before, jack up the rear of your truck by the rear axle, I don't like using the axle tubes, I prefer the diff case.
2. Crawl under the truck and mark a horizontal line about two inches long on the drive shaft with a piece of chalk, bright sharpie, or something.. when I say horizontal, I mean it should be parallel with the shaft itself, so draw the line on the shaft, and try to remember where it started, just spin the wheel until the line is facing right at you..
3. Now you can determine your gear ratio, which is the number of drive shaft revolutions that were made in relation to one tire revolution. For example, if your drive shaft rotated three and ~3/4 times in relation to one tire revolution, your gear ratio is 3.73s, if it rotated 4 and 1/10th times, then that's 4.10s, you probably half 3.42s or 3.73s.
So the gear ratio is the relation of your pinion gear to ring gear.
So in laymans terms, if someone had 3.42s and 265/75r16's, their gas mileage would be pretty good even for a TBI 350, but if that same person swapped out the 265s for 305/70R16s, and left the 3.42s, that would be hard on the truck and kill gas mileage, or if that person swapped out the 3.42s with 4.10s with 265s, those smaller tires would be spinning a lot more, and thus the truck would be a lot quicker off the line. But if you swapped out original 265s and 3.73s on my truck and put in 4.10s and 35s, it would compensate the larger tire for the lower gears, so gas mileage and speed would be about the same as stock, that's why people swap gears.
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