New rear gears for 65 230 manual, suggestions?

[Old65C10]

I just bought a 1965 C10, 230, 3 speed manual long fleet.

I love the truck, but on the road, anything over 60 MPH it really seems to be spinning at a high RPM. It feels like I am really pushing it.
I have no plans to do any heavy hauling, I have a 85 K30 for that. I just want to be able to run to the store etc. Where I live the speed limit is either 60 or 70. 60 is OK, but 70 it just won't go there.
What ratio would you suggest I re-gear to? It is a 65 so it should be the 12 bolt. Should I look for a good used rear from a 67-72 with better gears, or just re-gear the rear I have? Anything unique about the 65 12 bolt?
In the end, I want to use the C10 as a car, and save truck duty for my K30.

[Clyde65]

You need to find out what you have. Put both wheels off the ground, trans in nuetral, block the wheels!!!
Then mark the drive shaft and the wheel, turn wheel and countthose revolutions and the driveshaft as well. Divide and there is your gear ratio.
I’m suspecting you probably have 4:10’s, 3.73’s would be the highest you can go. Maybe you would benefit from a t5 swap instead??

[Old65C10]

Thanks. My goal is to keep the truck as stock looking as possible. I would rather not do a T5 swap because it would take away from the 3 on the Tree that it came with. A gear swap is un-seen and does not take away from the original looks.

[Captainfab]

I agree on first determining exactly what rear gears your truck has. I would guess 3.73's as it is the most common. Depending on your tire diameter, I would go with a 3.42 or 3.07 gear. The 3.07 gear will make the most noticable difference.

[67pete300]

I just did this check on my 65 230, three on the tree C10 and got 3.73. Which checks with my chassis manual.

[Old65C10]

So, being a 65, what other year trucks would have the same rear end for a swap, or should I just re-gear the original?

[curvedglass]

I have a 63 with the 230 and 3-speed. My previous owner swapped in a 3.08's. I can get it up to 70-75 ..... in about 5 minutes, but I can get there. I lost most of my off the line power but it cruises great and I get roughly 17.5-18+ mpg.

My future plan is to install the 3 speed OD I bought so I can keep the three on the tree and go back to 3.73's. End result would be a 2.90 something final drive ration in 3rd OD. Still looks stock. No hacking the floor.

Look around for a 3 speed OD. They are out there. The price is slightly more than having the rear rebuilt end to end. I had a mustang rear done by the local specialist and it was $1000 with everything being rebuilt or replaced. Trans is about $1400.

[Clyde65]

Regear the original. 65-69 1/2 have the same spline count tho.

[Old65C10]

Great, thank you all. I also have a 85 K30 Dually 454. It has almost the same issue, but its an auto (THM400). It hits about 65 and thats about it. However with it, the higher the MPH goes, that faster the gas gauge drops. I think it will tow a house if there are enough gas stations along the route.
Maybe 3:42 would be a good middle ground for the 65.

[Railroader]

Suggest you think about "curved glass's" suggestion on manual 3 speed OD. You can keep the shifter on the column and get cruising speed. I put one in my 63 and can now run 65/70 at 2000/2200 rpm's. Made a WORLD of difference.

Read through thread on 3 speed OD for details.