4.56 or 4.88 the burning question

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Jrgunn5150

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Stupid question but not fimiliar with gearing. i have a k3500 with a 350. 4.10 gears, 6in lift. if i was to go with the 5.13s, would i still be able to do 80mph without being ***** out? lol if you dont do 80 on the freeway here, you will get ran over lol. i know it would give it more low end


Yes, use the calculator Slowburb gave you, they are accurate to within a couple hundred RPM. People fear the gear, but they shouldn't.

Another thing to think of, and why I always go one step above, is bigger tires are heavier than stock, so it takes more to turn them just from the weight, as well as the height.
 

5spd Z71

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Plus you have a great rolling resistance. That much more tire on the road compared to stock. The tires I have measure 34.5", and with 4.56 gears, I'm at roughly 2250rpm at 65mph. About 2400rpm at 70mph. Although I never really drove the truck faster than that. So I'm fine with those rpm's.

Depends on what you use the truck for though. But since you're driving mostly in town, set it up for that.
 

plouth

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So it sounds like 5.13 is the way to go...I don't need this thing to do burnouts but having the little bit extra sounds right.
Another question I have is for the 5.7 where really is the sweet spot for rpm for the highway. I do need to get this thing to do 70 or 80 no problem on the highway, and do t want to kill what's left of the motor.
Also is it worth putting 5.13 in a 10 bolt? I don't offroad like crazy mostly a street pounder. The truck has had 37's and 373's for 7 years so I think the 10 bolt is not doing to bad.
Love to hear everyone's thoughts.
 

Jrgunn5150

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So it sounds like 5.13 is the way to go...I don't need this thing to do burnouts but having the little bit extra sounds right.
Another question I have is for the 5.7 where really is the sweet spot for rpm for the highway. I do need to get this thing to do 70 or 80 no problem on the highway, and do t want to kill what's left of the motor.
Also is it worth putting 5.13 in a 10 bolt? I don't offroad like crazy mostly a street pounder. The truck has had 37's and 373's for 7 years so I think the 10 bolt is not doing to bad.
Love to hear everyone's thoughts.

My personal opinion is, that I wouldn't put any money into the 10B. Just because if it does pop or you do start offroading it, it'll be money wasted. I find 14B SF's for under 200 really regularly.

I would say about 22-2400 rpm will keep the trans in lockup and happy under normal circumstances.
 
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