what rear end?

[evilokc]

I have an open gm 10 bolt right now. it has 308s and I would like to be in the 355 area with a posi. is a 10 bolt worth putting the work into or should I find a whole new rear end>

[mongocanfly]

is this the stock rearend? if so id upgrade to a new rearend with the gears and stuff you want...go find a good s1o rear with 3.42s and a g80

[NorCalGal]

Or you can pick up an 8.8 out of an explorer with posi 355 and disc brakes for $150.00 at pick n pull that's also the perfect width.

[mongocanfly]

^^^yep^^^forgot about the fudd explorer...

[jweb]

The Explorer axle is 59.5" which was a little narrow for me. I put one in my '51 and added 1" wheel spacers/adapters and it fits perfect. This also helps with the bolt pattern issue. They do have an offset housing which can be tricky if you plan to use a triangulated 4 link.

I believe a 99+ Mustang GT is closer to the width you would need and has a centered housing. These are more expensive than the Explorer and you would have to deal with the bolt pattern a different way. I don't know what gear ratios are available with these.

[Driver_WT]

Originally Posted by jweb

The Explorer axle is 59.5" which was a little narrow for me. I put one in my '51 and added 1" wheel spacers/adapters and it fits perfect. This also helps with the bolt pattern issue. They do have an offset housing which can be tricky if you plan to use a triangulated 4 link.

I believe a 99+ Mustang GT is closer to the width you would need and has a centered housing. These are more expensive than the Explorer and you would have to deal with the bolt pattern a different way. I don't know what gear ratios are available with these.

Mustang rear axle will also be for coil springs, but you can deal with that. I am upgrading to the Explorer rear axle with 3.73 gears. Should work great with my 700R4 trans with 0.70 overdrive.

[Mains52]

I've got a 3:08 posi I plan on using. I am building a highway cruiser so I don't need my truck to yank the front end off the ground. Who knows maybe Ill get tired of cruising and put something more snappy in in the future. Let us know how it goes.

[dsraven]

here is a ratio calculator that works for tire diameter/height, rear axle ratio and trans final drive ratio. it will give you rpm at highway speeds.

https://www.ringpinion.com/calculators/Calc_RPM.aspx

here is another calculator with a graphic for tire size comparisons.

https://tiresize.com/comparison/

[_Ogre]

all these answers and still no one knows what it's going into?

[hint]read my signature[hint]

[Erics51chevy]

Make sure when you buy the rear end mark which bearing cap is which side!! I was dumb enough to buy a 8.8 rear from a guy with no bearing caps! Doh! I was too excited to get some rear i didnt even think about it until i got home.

[evilokc]

its already in a 53 3100 with a 5.7 sbc and a 350 trans. its a weekend driver that I want to be peppy. my 308s are good but I would like it to feel a little punchier. I looked at an rpm calculator and I believe I can live with 3.42s. they will give me more off the line and not kill my motor when I get on the highway. my question was if you guys thought a 7.5 10 bolt rear end was worth upgrading. I read up as much as I could find and for my power output and driving style I believe my current rear end IS worth a gear change. will probably be my next move.

[DPete]

You sure about gearing down? I have the same set up and just put 308's w/ posi in. 15" wheels though that could make a difference if you are on tall wheels. I'm @ 2500 doing 70

[evilokc]

I have a little taller tires in the back but I really want it to have a torquier feel to it. I wont do much highway time for a while. I plan a 700r4 swap down the road.