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New Rear....what a difference

730 Views 5 Replies 6 Participants Last post by  carsavvycook
OK, I wasn't sure if I should paste this here, or in the driveline section. So I flipped a coin, this section won. The engine:

427 small block
240/246 Roller Cam
1.6 Rockers
Cam set on 108 centerline
700r4 trans
3000 Stall converter


I have spent the past few days afer work installing a new rear in my car. I went from a 3.07 Dana 36 to a 3.73 Dana 44. A bigger, stronger rear.

Well, forget the seat of pants stuff, because in my opinion that's just subjective garbage.

However, I have been trying like heck to get this car tuned.

Some of the issues include bucking and shuddering off the line when rolling into it slowly off the light. Also did the same thing on the highway between 50-65MPH. Also, there was a lean pop off the passenger side.

The roll off the line problem, CURED. The sputtering on the highway, CURED. THe poping, greatly reduced.

THe car isn't dialed in 100%, HOWEVER, it is a lot better than it was before the rear switch.
1 - 6 of 6 Posts
Heard a similar story from a buddy that had a cylinder head shop. Ford pickup with a mild 460 & auto trans. He had a stumble that neither he nor his engine building / dyno buddies could completely fix, but they all agreed on going to a 3.90 gear from a 3.25 - problem solved.
do you run an A/F gauge? Going to a higher gear can mask some problems since it lessens the load on the engine. Run a gauge just to see what it says, it's probably too much timing or too lean of a mixture.
How strong are the Dana 44's?

Hey guys,

I just picked up a Chevy Luv truck with a SBC 350 in it. Totally wild ball park guess on the 350 is between 300-400 HP. The Dana is a 3.73 posi. In general, will this rear end hold up to a beating at the drag strip with this motor? I could put a 9 inch it but if I don't have to go through all the trouble and expense of narrowing the 9 inch right now to fit under the bed I would rather not. Any input is greatly appreciated. I obviously know very little about the Dana differentials. Thanks.

Brent
One way to find out. Run it 'til it breaks, then worry about a replacement.
Jsup said:
OK, I wasn't sure if I should paste this here, or in the driveline section. So I flipped a coin, this section won. The engine:

427 small block
240/246 Roller Cam
1.6 Rockers
Cam set on 108 centerline
700r4 trans
3000 Stall converter


I have spent the past few days afer work installing a new rear in my car. I went from a 3.07 Dana 36 to a 3.73 Dana 44. A bigger, stronger rear.

Well, forget the seat of pants stuff, because in my opinion that's just subjective garbage.

However, I have been trying like heck to get this car tuned.

Some of the issues include bucking and shuddering off the line when rolling into it slowly off the light. Also did the same thing on the highway between 50-65MPH. Also, there was a lean pop off the passenger side.

The roll off the line problem, CURED. The sputtering on the highway, CURED. THe poping, greatly reduced.

THe car isn't dialed in 100%, HOWEVER, it is a lot better than it was before the rear switch.
I am glad to read this. I new you would be very happy with this gear change, but I did not think it would get rid of, or reduce that 'pop' we talked about.

It sounds to me that with just a little programing, and dialing in, your problems are solved.
1 - 6 of 6 Posts
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