Rear End Help

[eastcoastcivil]

I found a rear end that may be quicker than the Eaton I have with 4:10 gears. I have a 67 C20 2WD LWB with a 3 on the tree and a 350. I want to put a TH350 and a faster rear end./ Can anyone identify if this is a Dana rear end? What gears were stock with this...its a 1970 GMC C20 that was a 4 speed manual.

[68GMCCustom]

its a Dana...you have to look for the "44" or "60" on it to tell the difference.

[eastcoastcivil]

Where would I find the 44 or the 60 and what is the difference between them? Thanks in advance.

[eastcoastcivil]

No takers? LOL
Or is my question really common
knowledge and I should feel shame
for asking?

[67vetteal]

I'm with you on this one. Is there any source for Rear End info. on our trucks? Al W.

[68GMCCustom]

A Dana axle has the model number displayed as a raised numbering on the casting. From the rear it would be bottom right of the rear cover, on the casing. On the front, its to the right of the pinion shaft.

[LONGHAIR]

Originally Posted by eastcoastcivil

I found a rear end that may be quicker than the Eaton I have with 4:10 gears. I have a 67 C20 2WD LWB with a 3 on the tree and a 350. I want to put a TH350 and a faster rear end.

I am confused? First you say "quicker" ...and then at the end you say "faster"?
These are totally opposite things.
"Quicker" is standing start acceleration, which is a lower gear. Low gears accelerate quickly, but you run out of top end speed because of the increased RPM.

"Faster" is higher top speed, which requires a higher gear. High gears litterally translate into higher top speed at the same engine RPM.

[70-Chevy]

This link might help

http://www.chevellestuff.com/qd/gene..._axle_info.htm

[Willys47]

that looks like a dana 60 to me and it would be a stronger diff than a 12 bolt diff

[cdowns]

did you ever stop to think that maybe more horsepower will solve the problem?? a 411 is a nice rear but at probally less than 150horsepower to the rear wheels there just not much any rear is going to do for you

[Longhorn Man]

the dana 60 in the 3/4 tons is not very strong, they are known for shattering the axle shafts... esp in 4x4 aplications

[eastcoastcivil]

ok...I have a 350 bored out so power is not the problem...I have 4:10 which means I have great power at the start (quicker I guess)...but I want to make the top end better so I am not screaming at 3000 RPM cruising down the highway at 50 MPH. lol
I live on a road that has a 60 MPH speed limit at the end of my driveway.

[Chevydude56]

Have you thought about using a 700R4 instead of a TH350?

[davebloomer]

www.bowtieoverdrives.com

Keep the 4.10's and go with a 700R4 or 2004R instead of a turbo 350. IMO adding another gear is way more practical for increasing top speed... Because no one wants it to take 2 hours to get to that top speed. Unless you're looking for a much higher top speed in which case you should do overdrive and swap gears out.

[davebloomer]

Originally Posted by Chevydude56

Have you thought about using a 700R4 instead of a TH350?

ahh you beat me to it...

[68GMCCustom]

Originally Posted by Longhorn Man

the dana 60 in the 3/4 tons is not very strong, they are known for shattering the axle shafts... esp in 4x4 aplications

Really? I always thought the Dana 60 was one of the top performance axles of choice, short of a 9" Ford. 60's and early 70's Hemi and 440/6pk Chrysler's had the Dana 60 since it could hold up to the torque. Jeeps run either Dana44/Dana60 front rear setups, or go bigger with Dana 60's up front and something even bigger (Dana 80, 14 bolt?) out back. I would guess that most folks would change out the axles on a 3/4 ton diff to go from 8 lugs to 6 or even 5 anyway wouldn't they?

I ask because a Dana 60 was what I had planned on upgrading to when my new LSx motor gets installed... and a set of drag radials breaks the current 12 bolt.

[ERASER5]

Here is a picture from my gallery. Look for a 60 or a 44 here. The D60 had 3.54, 3.73, and 4.10 gears. Possibly lower, but I doubt it. The after market should have more possibilities.

[eastcoastcivil]

I have but would be doing the work myself and would not know how to wire a 700R4 I guess. I was told a short tail TH350 woould be a direct swap without having to modify my axle since I now have a 3 speed Saginaw. I thought it would be easiest.

Would the 2004R be easier to set up than the 700R4?

[67vetteal]

Originally Posted by eastcoastcivil

I have but would be doing the work myself and would not know how to wire a 700R4 I guess. I was told a short tail TH350 woould be a direct swap without having to modify my axle since I now have a 3 speed Saginaw. I thought it would be easiest.

Would the 2004R be easier to set up than the 700R4?

Google it when you have lots of time to study. Al W.

[capev86]

i am putting in a 4.10 in my 72 burb c20 w/ ho52 (has 4.57 now) and plan to add the factory 65-69 borg warner overdrive to the 3 on the tree (replaces the tail shaft). that will give me a decent rear gear but give a better ratio on the highway than a straight 3.08. you can't beat a 3.73/4.10 with a good overdrive. the 200-4r is a direct swap for the turbo 350, whereas the 700 is longer than either auto or the 3OT and will require the driveshaft be shortened. i also suggest a lockup converter to reduce excess heat in the trans and save every last engine rev you can (advantages normally reserved for manual transmissions). all in all its a clean install.

[Jacfourteen]

Originally Posted by ERASER5

Here is a picture from my gallery. Look for a 60 or a 44 here. The D60 had 3.54, 3.73, and 4.10 gears. Possibly lower, but I doubt it. The after market should have more possibilities.

I have a 8 lug dana 60 and the 60 isn't cast in that spot, it is on the passenger side lower rear of the housing just below where the axle tube comes out. If you look in lmc (here's the link) there is a great illustration that shows how to ID the danas. Also there are even lower gears that came in these stock, mine has a 4.56 and there were some that had 5.13's. So you might want to pull the cover and find out what is in there for sure (not to mention if it is open or posi and to check condition).

[eastcoastcivil]

So I found a tranny and the guy tells me it is a 200-4R but I think it is a 700R. Can anyone identify this? If it is a 700R I heard that it was more difficult to wire...what has to be wired? Thanks

[68GMCCustom]

that doesn't look like my 200-4r

[eastcoastcivil]

So I went back to see the guy who sold me the 700R and swaped with him for a rebuilt 200-4R which has been rebuilt with a shift kit installed. Shouold be just what I am looking for with my C20.

[srr]

Just make sure you get that T.V. set up correctly before you ever move the truck or you'll ruin the transmission. It's critical.