Big Block, stock torque converter, triple stick Tcases, deep-deep gears, and giant tires, is a combination I think we can all get behind.
CK5
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Offsetting rear end gears with power?
- Thread starter mark84k5
- Start date
We are all behind that because it’s slow af
I guess that would make me "that guy"!?
I think post #2 was the winner so far. Diesels been doin it with boost for a long time. I always thought it feels kinda like driving around on a giant rubber band? torque against the gearing and then hold on for the power band when it gets there.
in a 350 or 454, low end torque helps, but expectations still may not be met. most of the k5s my buddys have built ended up with 35 inch tires and had 350 engines... 4:11 and 4:56 gears, and 700r4 transmissions. Meh. I think mine scoots around better
I have a 3:73 gearing on 35 inch tires. it gets around fine, but is not a hot rod. gearing is a little tall pulling away from a stop, and I'm not winning a race against a 4.8, 5.3, OR that 6.0 you wanted, but having the manual trans helps my 350 put a little more HP to the ground though.
hey... 3:42 gears were AWESOME (in my camaro). with that in the rear end, and 2 overdrives? Borat says, "Veery NIIIIIiiiiice"
in the t-56, 5th gear is similar to the OD gear in most of the 4 speed autos... and 6th gear was a 40 percent overdrive gear! I regularly got over 30mpg from the 350 cruising around 70mph.
Maybe you just need more power and torque, need 3:42 gears, and need to reshape the body like a giant dart, and loose about 1500 pounds??? instant hot rod. easy peasy.
So in a captain obvious type realm, I will say with the axle size and tire size staying the same the bigger engine will deal with the mismatch better. 4.10’s with 35’s is much more usable with an 8.1 pushing them vs a smaller engine like a 5.3 I had in prior.
It’s an interesting comparison because as others have noted gearing will give the better performance for the smaller engine. But a larger engine that builds a lot more torque down low can overcome the lack of mechanical advantage the less than ideal gear/tire size combo has. Having the lower overall final drive ratio with Od and 4.10 vs 4.56 I was looking at doing also allow the 8.1 to eek out some decent fuel economy on the highway vs my buddies with the same 8.1, trans and tire size but 4.56 gears.
Granted I could have easily regeared for the cost of the 8.1 swap and kept the 5.3 but having more power down low was the driving factor.
It’s an interesting comparison because as others have noted gearing will give the better performance for the smaller engine. But a larger engine that builds a lot more torque down low can overcome the lack of mechanical advantage the less than ideal gear/tire size combo has. Having the lower overall final drive ratio with Od and 4.10 vs 4.56 I was looking at doing also allow the 8.1 to eek out some decent fuel economy on the highway vs my buddies with the same 8.1, trans and tire size but 4.56 gears.
Granted I could have easily regeared for the cost of the 8.1 swap and kept the 5.3 but having more power down low was the driving factor.
And because
Big block
Big block
so i dont know if this will help . but one of my builds i did some playing around for power and more power but highway rpm goodness .
stock 31" tires and 4.10 gear with th400 at 70 = 3,290 rpm .
35" tires and 4.10 gear at 70 = 2,910 rpm . non over drive .
35" tires and 5.13 gears with a 4L80-e swap at 70 = 2,590 rpm .
so use this to help pick what you need for driver or trail or towing .
and yes this one is getting a 454 or possible 8.1L vortec swap .
stock 31" tires and 4.10 gear with th400 at 70 = 3,290 rpm .
35" tires and 4.10 gear at 70 = 2,910 rpm . non over drive .
35" tires and 5.13 gears with a 4L80-e swap at 70 = 2,590 rpm .
so use this to help pick what you need for driver or trail or towing .
and yes this one is getting a 454 or possible 8.1L vortec swap .
Here's a good rpm/gear ratio/tire size calculator.
You can find factory axles with 4:10's and 4:56's pretty cheap.
Gears are the single biggest bang for the buck for torque.
FYI, every inch added to tire size effectively raises the gear ratio .1.
For example, a 4.10 with 6 inch taller tires makes the gear act like a 3:50.
You can find factory axles with 4:10's and 4:56's pretty cheap.
Gears are the single biggest bang for the buck for torque.
FYI, every inch added to tire size effectively raises the gear ratio .1.
For example, a 4.10 with 6 inch taller tires makes the gear act like a 3:50.
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42" SS, 5.38/1,203/205/400/496 = TRAIL PLUG 
I ran 40" boggers with 3.73s, but had a big block lol. I'd say gears, then do an OD. 4.10s for 31 or 33s, 4.56s for 35s. I have a 99 Yukon with a 350/4L60, 3.73s and roughly 31s, and scoots pretty good...
So what gears are in it now? 3:08? For long term high-speed driving you really want/need an O/D transmission, or just stick with the wimpy gears. Another option is an external O/D box, like the Ranger or Gear Vendors, but that's probably more costly than swapping to a 700R-4, which could probably be done with all factory parts. Plus, if this is a short bed or Blazer we're talking about, an external O/D will probably make the rear driveshaft too short. Have you considered NV3500 or NV4500?
The gears are 2.74 or something like that. Since I posted this tread I have changed what I’m gonna do. I am having a 4l80 built right now and will have the gears changed to 3.55 or maybe 3.73. This truck is gonna have 31x10.50 tires and it will not be seeing heavy off road use. And I have a 5.3 sitting in the back of my k5.
That’ll be perfect.
3.73, or higher numerical.
With 3.73 at 65 you will be at 2000 rpm. But at 55 you might be on the converter stall, and out of the power band.
With 3.73 at 65 you will be at 2000 rpm. But at 55 you might be on the converter stall, and out of the power band.
I didn’t even think about that!
I would look into gears and transmission. Lower gears to make it quicker off the line and a transmission with over drive to keep your highway rpms down and mpg decent. Then when you add engine mods even better. Basically all you have to change is everything. (haha)
The standard CK5 answer to these issues.
Lift the radiator cap, replace and upgrade everything under it.
Gas mileage for a brick is oxymoron
Gears are torque multipliers. It takes a certain amount of torque to push a truck at a certain speed and that can come from an engine producing a small amount of torque with a lot of gearing or a large amount of torque with less gearing. That's all there is to it. This is why trucks with super torquey diesels can be super happy with big tires and low number gears. I know a lot of dodge guys like 3.54 and 35s for example. A truck with a little engine (toyota stuff maybe) will want 7.17s to do some of the same work and still might not get it done. We have a '91 sidekick around here with stock 5.13s and the stock little tires. It gets around pretty good for what it is but I've been on a long trip with one of those running 35s and he couldn't keep up on the road at all. 55mph was about all it liked on the flat. Just no way to make enough torque.
