Advice Pleas on rear end.

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imager

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Advice Pleas on rear end.

Ok first some info on the car I have. It a 1966 Plymouth barracuda that one of the previous owners has put in a 318 with 360 heads and edelbrock 316-360 intake with a 600cfm carburetor.

I had to take apart the top end and replace all the gaskets and rebuild the carburetor. It’s all back together now and runs ok. When you get to about 45-50 MPH you get a roar out of the rear end so I’m sure I need to go thru it 100% and replace all the carrier bearings.
My plans for this car are to have a good driver with a strong motor and drive train. The game plan is to put SB 360 with a 727 transmission in this car.
My question is should I just rebuild the rear end that is in the car or should I start fresh and if so what should I be looking for and what would work best with my setup.

Thank you for your time.

Will
 
What rear end is currently in the car? I'd suspect a 7 & 1/4 SBP. Worth rebuilding? Up to you but others likely to say no. I'd probably be looking for an A Body 8.25 (LBP) or an A Body 8.75 (most likely SBP) or 65-70 B Body 8.25 (LBP) and use different offset wheels. I'm personally going to use an 8.75 in my 3 early A's. My 2c
 
You're sure the roar is in the rear and not a U joint ?
I wouldn't spend money to rebuild a 7.25. You could pick up a few used ones for a lot less than parts to rebuild will cost.
 
Yes it has the 7.25 in it now. Sorry forgot to say that i replaced the U joints as well. I was hoping that was what was wrong but no luck for me :)...

Sorry for all the questions but what is (SBP and LBP)?

Also if i go with 8.75 will i have to cut it down or do any major mods to it?

Thanks again for you help and info.
 
SBP = small bolt pattern 5 on 4 inch circle. LBP = large bolt pattern 5 on 4.5 inch circle.
8.75 a-body rear will bolt right in but those would be SBP only. 8.75 from a b-body mopar would be LBP but is also a little wider. The 8.75 is most popular with the performance minded and can be quite expensive.
 
If it's a whine, it's probably gears and not worth fixing. If it's a rumble, it's probably a bearing and depending on which one(s) it is, it might be worth fixing if you just need to keep it on the road. Axle bearings are easy, carrier bearings are a bit harder, and if the pinion bearings are bad, get another rear. In the long run, go with an 8 3/4 if you need the strength or an 8 1/4 if you just need a bit more and want to change to the big bolt pattern. With a 7 1/4 in there, you're just on borrowed time.....
 
Thank you all for your help and advise. I think i will start looking for an A-Body 8 1/4 Big Bolt.

Will





cudamark said:
If it's a whine, it's probably gears and not worth fixing. If it's a rumble, it's probably a bearing and depending on which one(s) it is, it might be worth fixing if you just need to keep it on the road. Axle bearings are easy, carrier bearings are a bit harder, and if the pinion bearings are bad, get another rear. In the long run, go with an 8 3/4 if you need the strength or an 8 1/4 if you just need a bit more and want to change to the big bolt pattern. With a 7 1/4 in there, you're just on borrowed time.....
Click to expand...
 
How much horsepower do you plan to have in the 360? Do you plan to only drive it on the street or maybe do some drag racing with it? Will you be putting sticky street tires or a set of drag slicks on if you do plan to race it? Just things to consider before you start to build. That way you can build what you need once in stead of having to do it twice, like me! Much cheaper and easier to do it once! I probably wouldn't spend to much time or money on the 7.25 rear, they are pretty weak. If that's what you want just to keep driving it, maybe you could find one that someone is getting ready to swap out or has recently pulled out and they know it is in good shape. Otherwise I'd say an 8.75 or bigger depending on what you plan to do with it.

Just my 2 cents, Tony
 
I would like a mild 360 something that sounds great and a good driver. We do not have a drag strip and i don't think it will ever see one anyway.

And your 2 cents is always welcome

Will
 
Sounds like the 8.25 LBP would probably be a good swap for you. Good luck on the project!

Tony
 
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