good engine speed

[gmcman]

I'm trying to calculate gearing for the tires I want and was wondering what is a decent engine rpm for a 350 chev. I have a 350 with sm465, 208 t-case with 31's and 2.73 gears. I want 35's and possibly 3.73 gears but at 75 mph rpms will be around 2800.With the gearing I have ,2200 rpms at 75 mph but not much power on the hills. Where do the 350's work the best for mileage and power?

 

[Hogback Fabrication]

I'm trying to calculate gearing for the tires I want and was wondering what is a decent engine rpm for a 350 chev. I have a 350 with sm465, 208 t-case with 31's and 2.73 gears. I want 35's and possibly 3.73 gears but at 75 mph rpms will be around 2800.With the gearing I have ,2200 rpms at 75 mph but not much power on the hills. Where do the 350's work the best for mileage and power?

With 3.73's, you will be spinning 2686 RPM which is a good compromise IMO. Plus you can probably find axles that already have 3.73's and swap them under your truck to save a bunch of money on gears and install.

 

[original balzer]

Thats kinda like asking what color red is the reddest.
But in a general kinda way 2000 RPM is a good cruising RPM to shoot for.

If we knew more about your 350 it would bew easier to tell you.

 

[gmcman]

None of the local yards have any rearends. I have a 12 bolt but the carrier and internals are messed up. The ones I have found are all highway gears like 3.08. Not much around this area. May have to try a little farther away.

 

[4X4HIGH]

Most Chevy engines like anything from 2200-2500 at cruise speeds. With that being said if you want your cruise speed to be 75 mph and you're going to run a 35" tire (all brands measure slightly different but most come in under stated sizing) then you want 3.73 or numerically smaller.

 

[Russell]

My old 350 used to run 3200 rpm at 120 km/h with 4.10s and little bitty tires. Never had any problems running it that way, less trying to make it between gas stations on longer trips.

 

[chulisohombre]

chevy small blocks tend to get the best mileage at the 2300 rpm range.so like was said,2200 to 2500 would be the best place to be.if u want a little more performance go with 410 gearing.u may have to run a little slower to keep the rpms down,but on trails its worth it.if you are not worried about trail performance and drive mostly road miles.373 would be adaquate to get you close to stock gearing with 35 inch tires.i went from 373 to 410 and like it better.moderate change but you can feel the difference when runnin in town or in stop and go traffic.i also dont run it over 65 though because im pushing 3000 rpm with 35 inch tires.