Need schooling on the 8 1/4 carrier breaks.....if any

[Cranky1]

Or is there a site that I can 'learnt' from? Would like to slam in some 3.90 gears or even 4.30's in my beater 95 Dakota V6 since I can't find a V8 truck. Wouldn't mind doing the 96 too since it acts like it's even slower. Is it correct that these are pretty much a wham bam thank you mam gear swap if using factory gears? I know someone that did that in a 9 1/4 equipped 2000 truck and they were quiet. Sick of this slow no guts stuff. Can't even put on decent size tires without losing pep from it. And don't do much freeway running anymore so even steeper gears would be fine with me. Right now they have 3.55's

 

[GE-Truck Master]

There’s an in depth section about 8-1/4 rear axles and carrier breaks over on For A bodies only. The carrier break to my knowledge goes 2.18-2.45:1 and then 2.56-4.88. I don’t think your going to find the high ratio carrier in a Dakota, but I have a friend who has found several 2.45:1 D150 8-1/4 rear axles. While off topic, those are great for interstate miles trucks with a v8 and an np 435. His is going together with a 5.9 magnum, Oregon cam, magnum exhaust manifolds, and an SP2P converted to magnum vertical intake bolts. Here the complete all you need to know on the 27 spline 8-1/4. Just click this link.
The 8 1/4 thread

 

[Cranky1]

Yeah...been looking at that.....thinking about stuffing an 8 3/4 under the thing. Got one plus several 3rd members all the way up to 4.88

 

[my5thmopar]

I did 4.56 in my 2002 Dak. Way too much even on 35s. I regularly abused it without issues.

 

[GE-Truck Master]

About to sling a 4.56 sure grip 8-1/4 under a '71 Duster with 28 inch (L60-15) tires. There's only three miles of four lane highway
on the way to our local drag strip (1/8 mile) that's threatening to reopen so the 3000 rpm or so rpm @ 58 mph (accounting for an inch of tire growth at speed) shouldn't be too awful to live with. It's a shame that 4.30 gears aren't as common for them as they used to be, though.

 

[7mopar]

About to sling a 4.56 sure grip 8-1/4 under a '71 Duster with 28 inch (L60-15) tires. There's only three miles of four lane highway
on the way to our local drag strip (1/8 mile) that's threatening to reopen so the 3000 rpm or so rpm @ 58 mph (accounting for an inch of tire growth at speed) shouldn't be too awful to live with. It's a shame that 4.30 gears aren't as common for them as they used to be, though.

Not sure how you are figuring that. With 9.50/16.5's that's about 3200 rpm. think they are about 31 inches.

 

[HALIFAXHOPS]

We definately beat up the 8.25 on FABO. Lots of good info in there.

 

[GE-Truck Master]

Not sure how you are figuring that. With 9.50/16.5's that's about 3200 rpm. think they are about 31 inches.

They're Kelsey tire Goodyear Polyglas. The listings show the measurement at 28X9, and with the 7.5 inch wide ET IV mags (I'd really like to have an 8-1/2-9 inch wide wheel) I can expect at least an inch of tire growth at highway speed.