65 3/4 ton questions

[hotrod66]

Okay I am really familiar with 60-66 but this is my first hd truck and know nothing other than it has a 292. My questions are what rear axle is in this thing and what is the most likely ratio? Because 3rd gear fills like first in my 66 that has 3:08s. Its has a granny 4 spd is this a sm420? Oddly enough this is my first truck 4 speed i have owned, most have had 3 speeds. the truck is almost completely factory stock with the exception of the air cleaner, tires and wheels. any way thanks for looking.

[seabeevin]

mine has 4.56. looks like the eaton rear. if I am correct, they were 4.11 or 4.56. also the bearings cost about 6 bills for a full set. I think mine is the HO72. I need a set of 4.11 gears and if I cant get a set, im gonna swap in a dana or corp 14.

[LostMy65]

My 66 had that Eaton with 4:56.
.
Don't spend the money on that rear.
.
If you decide to go to a 14-Bolt as I did, here is a thread:
http://67-72chevytrucks.com/vboard/s...d.php?t=550878

[hotrod66]

Originally Posted by LostMy65

My 66 had that Eaton with 4:56.
.
Don't spend the money on that rear.
.
If you decide to go to a 14-Bolt as I did, here is a thread:
http://67-72chevytrucks.com/vboard/s...d.php?t=550878

thanks will see about finding a cheep 80s donor truck i know of a 72 3/4 with the front disks wonder if its a eaton . where do i get the captain fab brackets from?

[Captainfab]

That '72 C20 might have a Dana 60 under it, which will bolt right in under your '65. If it was a big block with auto truck it will have 3.54 gears.

Here is the for sale thread for my trailing arm mounts.

http://www.67-72chevytrucks.com/vboa...d.php?t=620836

Originally Posted by hotrod66

thanks will see about finding a cheep 80s donor truck i know of a 72 3/4 with the front disks wonder if its a eaton . where do i get the captain fab brackets from?

[hotrod66]

Originally Posted by Captainfab

That '72 C20 might have a Dana 60 under it, which will bolt right in under your '65. If it was a big block with auto truck it will have 3.54 gears.

Here is the for sale thread for my trailing arm mounts.

http://www.67-72chevytrucks.com/vboa...d.php?t=620836

cool thanks the 72 is a option i will look at first its a small block and 4 speed truck if not i will go with the later axil

[earl84]

Looks like the Eaton HO52 I had in mine. Most had 4.56 gears, mine had 4.11, but I replaced with a 14 bolt, using Captain's trailing arm mounts. The transmission is most likely the SM 420 with granny low first gear. Great for working around the farm, maybe not the best for highway cruising, especially if the rearend is 4.56 gears. But there is certainly some cool factor for originality, depends on how you are going to use your truck. Start with a solid plan first.

[hotrod66]

Originally Posted by earl84

Looks like the Eaton HO52 I had in mine. Most had 4.56 gears, mine had 4.11, but I replaced with a 14 bolt, using Captain's trailing arm mounts. The transmission is most likely the SM 420 with granny low first gear. Great for working around the farm, maybe not the best for highway cruising, especially if the rearend is 4.56 gears. But there is certainly some cool factor for originality, depends on how you are going to use your truck. Start with a solid plan first.

Plan on using it as a hauler and to run to the junkyards probably only use it on the weekends. I would like to swap my nv3500 (dont know if thats a good idea) into it and disc brakes up front. For right now i plan to leave it alone until i finish my short 66 truck.

[66Submarine]

Eaton HO52 rear and SM420 trans.

4.57:1 was standard, and 4.11:1 was optional. Check and see what you have, though; both my C30's came with later 4.10's in them.

It's probably fine, unless someone ran all the oil out of it at some point.

The bearings for the Eaton rears are cost-prohibitive, but I don't really see much of a reason you'd ever need to buy them. The Eaton is a third-member type rear (unlike the 14 bolt and Dana 60), so all you have to do is pop the axles out (8 bolts on both the hub flanges) and you can unbolt the old one and bolt the new one right back in. There's not a lot of demand for them in 2014, so they are normally cheap to buy if you need another.

The lack of gears taller than 4.10:1 is a factor if you are doing a lot of highway driving without an overdrive, but I don't see that being any trouble if you're going to use a NV4500 OD trans.

The 14 bolt is also great, but if it ain't broke...

[hotrod66]

Originally Posted by 66Submarine

Eaton HO52 rear and SM420 trans.

4.57:1 was standard, and 4.11:1 was optional. Check and see what you have, though; both my C30's came with later 4.10's in them.

It's probably fine, unless someone ran all the oil out of it at some point.

The bearings for the Eaton rears are cost-prohibitive, but I don't really see much of a reason you'd ever need to buy them. The Eaton is a third-member type rear (unlike the 14 bolt and Dana 60), so all you have to do is pop the axles out (8 bolts on both the hub flanges) and you can unbolt the old one and bolt the new one right back in. There's not a lot of demand for them in 2014, so they are normally cheap to buy if you need another.

The lack of gears taller than 4.10:1 is a factor if you are doing a lot of highway driving without an overdrive, but I don't see that being any trouble if you're going to use a NV4500 OD trans.

The 14 bolt is also great, but if it ain't broke...

the highway is a must where i live, surrounded on 4 sides by intersecting highways. would like to have 4.11s guess i will check and see what they are. has any one put the lighter duty nv3500 in a hd truck?

[66Submarine]

Originally Posted by hotrod66

the highway is a must where i live, surrounded on 4 sides by intersecting highways. would like to have 4.11s guess i will check and see what they are.

How fast are you planning on cruising? I hear Tejas is pretty bad about that.

[hotrod66]

Originally Posted by 66Submarine

How fast are you planning on cruising? I hear Tejas is pretty bad about that.

speed limit is for the most part 60-65 in fort worth get out away from the city its 70-75 my short truck no problem it has 3.08s cruses 70 @2200. im thinking the 65 is gonna need overdrive

[66Submarine]

Originally Posted by hotrod66

speed limit is for the most part 60-65 in fort worth get out away from the city its 70-75 my short truck no problem it has 3.08s cruses 70 @2200. im thinking the 65 is gonna need overdrive

What do people actually drive? I'm surprised if they only go 75!

I actually drive 70 sometimes (when traffic dictates) and go 65 frequently on longer trips.

'65 Chevrolet C30 towing at 65MPH - YouTube

[hotrod66]

Originally Posted by 66Submarine

What do people actually drive? I'm surprised if they only go 75!

I actually drive 70 sometimes (when traffic dictates) and go 65 frequently on longer trips.
'65 Chevrolet C30 towing at 65MPH - YouTube

usually 5 miles over the speed limit some times more. what size tires do you have?

[66Submarine]

Originally Posted by hotrod66

usually 5 miles over the speed limit some times more. what size tires do you have?

235/85R16 on the back and 245/75R16 on the front. About ten over is kind of average around here IME.