250i6 mods for Highway Driving

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Tdwmaxwell

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Location
Athens GA
First Name
Tyler
Truck Year
1982
Truck Model
c10
Engine Size
250
At the moment I drive a 1982 C10 with the 250i6 and the SM465 transmission, don't know what rear end. I'm looking to make it a bit more comfortable as a highway cruiser. I've been doing more highway driving recently and it feels like I put a lot of strain on the engine (I don't currently have a tachometer so I have almost no idea what my RPMs are). I've been thinking about doing an engine swap to a V8 but was wondering if I should try changing the gearing first. Any recommendations about what I should try to make highways more comfortable?
 

Grit dog

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Auburn, Washington
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Todd
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1986, 1977
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K20, C10
Engine Size
454, 350
If it’s an original 6cyl I’d be surprised if it has steep gears. But if that’s what you’re referring to, a V8 won’t help high rpm’s.
If your issue is just it doesn’t have enough power then more power is the solution.
 

ali_c20

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Austria
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Alexander
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1974, 1979
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C20, K5
Engine Size
350, 350
Welcome from Austria. Are you happy with the original engine and want too keep it? If yes I would install a tachometer (I prefer to have a tach in all of my cars) and check the rear end ratio. Tire size is also related to engine rpm.
You can use a Engine rpm calculator to get the rpm for current setup and the effects of the changes you want to make. No need for a tach then.

With that data I would see what needs to be done to achieve the desired goal.

This one has a list of popular transmission gear ratios:

https://www.crawlpedia.com/rpm_gear_calculator.htm
 

Vbb199

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Salisbury NC
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Vince
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89 Suburban R1500, 79 C10
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350, 502
Look in the glovebox and take a pic of the sticker and upload it. We can figure out your axle ratio from the SPID....
Or, compare for yourself.

I believe it'll be a GUx code, like for example, GU6 is 3.42, and GU4 is 3.08.

Assuming its the original rear gears, we can go from there and reccomend a change that'd suit you
 

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