rear end swap on a 49 Plymouth

Alright... jacked up Big Blue's ass end, and mocked it up with the new 8 3/4 rear end. The 49 Plymouth rear, factory, is 53 1/4" overall, with perches 41 1/2" between the perches. It's not easy to see in the picture, but the stock perches are really skinny compared to the stock 8 3/4 perches.

The 8 3/4 rear is 54 7/8" overall, with 44 1/2" on center between the perches. The overall difference is only 1 5/8", so I doubt it'll be noticed on a racehorse. The perches will have to be swapped and moved around a little... but I think I can make it happen without tooo much trouble.

I have a line on a few different center sections, so I'll be looking at a few this coming week, as we take a break for Turkey Day!!!

 

That 8 3/4 rear is the best choice you could have made. If you ever decide to upgrade to something with 'way too much power, you will have the rear end to take it!

 

You guys are DRIVING ME NUTS with this backing plate to backing measurement BULLSHIT! The only way to measure a rear axle for width, ACCURATELY, is outside of the drum, the wheel mounting surface to wheel mounting surface. Rear brake drum and axle offsets differ enough to make a significant difference in what you end up with. Since it is usually the inside of the fender wheel openings that is the limiting factor on axle width, the MOST CORRECT place to start is with the wheels and tires you plan to use. Set them up at the width of your inside fender to inside fender, less an adequate clearance amount, say 1 1/2" total, then measure between the inside of the wheel mounting surfaces and see what rear axle width you can use with that wheel/tire/fender combo. Adjustments can be made in wheels or tires if need be, but that is a great place to start.

 

sorry i missed this...yep the driveshaft was uncut just switched u joints to a crossover....origional w/external clips to metric w/internal clips...

 

The '48 Plymouth we just finished got a Ford 9" rear with a T-5 Tranny, all bolted up to a 392 Hemi.

 

BTW, the common rear leaf spring width in the 60-80s is 2.5". This is the perch that is easy to find.
http://www.summitracing.com/parts/SUM-720025
The ones on my 40 and probably on your 49 are 2 inches wide.
You will have to find those, try a trailer place or search online.

An 8 3/4 axle tube is usually 3 inches.

Gotta agree with Hnstray, measure from the face where the wheel bolts up.

 

The perches are an 1 7/8 on my 47 d24.

 

Frankie, are your springs wrapped? Mine are, maybe that's the diff....
I didn't measure the spread of the holes in the plate, just the spring.

 

Wrapped...but it's been so long since I measured, 8 years, maybe my brain has become unwrapped

 

Ohhh... that's suhweet lookin'. I dunno if I have the time/space to pull the whole body off, but seeing the whole driveline laid out like that does give me pause. It would make lining everything up so much easier!

Oh yeah... and the springs are wrapped on mine too! (see earlier pic)

 

Secured some more bits for the rear end... 3.55 geared center section, a driveshaft (will need trimming to length), and a few brake parts for my rear end. Does anyone have a pic/ diagram/ exploded view of what Mopar B-body rear brakes (11" x 2.5") look like. Finding a picture online is proving murder. It's like trying to put together a jigsaw puzzle without the picture! I think I've found everything I'll need at Napa to make the brakes work, but I want to be sure I have all the goodies before I attempt piecing it together!

 

How's this?

 

How's this?
http://www.moparts.org/Tech/Archive/brake/2.html

 

Perfect... diagrams and pictures! Thanks RJ & Rod!

 

i'm telling you guys jeep cherokee it's a dana 30 so it has tons of aftermarket support if need be. and it's 1/8 inch narrower that's 1/16 per side. cut the perches off add yours and your done. i don't get all the hoops your jumping through. and it's the same lug pattern.

 

It's rumored that a 1957or8 Ford 9 inch will bolt under a 49-52 Mopar with no modifications. The only hard part is finding one.

I'm happy with the small Valiant rear under my '50 Dodge only because it works well with the drivetrain. If I ever upgrade the powerplant, though, I will definitely have to find a beefier rear.

I like the idea of a Cherokee rearend because they are so plentiful and easy to get parts for. That's probably the route I will go in the future. Thanks Glendale for heads up on that.

 

Second to that. I swapped my '46 Dodge rear into Jeep unit and it really was a snap.

 

So glad I found this post.... Thanks

 

Hello gentleman.... Does that rear end HAVE to be from a Cherokee? If so what years shouldni be hunting for? Hope to get a response.........
Thanks in advance, for your time and knowledge

 

Explorer is also a good fit.
Look here for some additional info: http://www.qualityengineeredcomponents.com/?page_id=1023

Tell us about your project.

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I picked up this car, from a house broker, bought house at auction, this was in the garage. Got the car dirt cheap. With a butchered firewall. Now i just put in a 318 small block, with a 727. Don't know the history of the car, and the current rear axle doesn't match the yoke from the tranny. So I have to swap it, because a custom drive shaft is costing me 500$. Now that motor and tranny are in, I'm doing the templates for the fire wall... Am I working backwards? ...... To some of you gentleman, possibly. But I have reasons for my madness......... I appreciate the link 73RR. and thanks again for the intel.

 

You may also want to join up over at www.p15-d24.com so you have access to info on that generation of Mopar.

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looks like a limited slip for sure.what do you have in the 260 as far as pistons.

 

The post you replied to is over six years old. The thread has been 'reactivated' in the last few posts by a newbie doing a similar conversion. I don't know how many times I have got caught up in a thread only to discover (later) it is ancient....thanks for keeping me company

Ray

 

Yeah, Pete has been absent for some time now as his new job at the Pentagon no doubt has him busy....
Most of the engine details are buried in the thread and yes, it turned out real sweet.

I'm hoping that Jose starts his own build thread...hint...hint...

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I don't care how old the thread is I'm happy to help.
This is my 47 Plymouth with a blueprint motors 383 stroker. Chevy rear end 8.5. Stock suspension with a little help from a torch and lowing blocks.
It's scary fast and has been to Vegas and back with no problems. Leaving for the Viva Las Vegas show next Thursday.