Dart 8 1/4 to D60 lots oh stuff to figure out

[Jimmy]

Please look at my research and tell me if I'm on the right track, when I have it all figured out and the parts in hand I will be taking it to a pro for cutting and welding just want to cut down on cost by having all my ducks in a row snd knowing exactly what I want them to do.

In there = 8 1/4
A)Flange to Flange =51.4
B)leaf center to leaf center =43.02
C)Center line of axle to center of universal joint =11.69

going in =
D 60 30 spline full floating 8 BP 89 3/4 ton dodge pu
A) Flange to Flange =56.5
B) leaf center to leaf center =46.00
C) Center line of axle to center of universal joint =13.47
crkd
D) Axle total width = 60.125
E) Pass axle tube = 18.03125
F) Drivers axle tube = 19.40625
G) Drives axle length= 29.75
H) Pass axle length= 28.375 27.125
I) Total tube length= 37.4375
J) Required bar length= 43.25 ? don't know what bar this is.

Needed parts
A)perches
B)8 3/4 end hubs 10 "Drum brakes or disc conversion BBP
C)Custom length 30 spline BBP axles from Moser or cut,

re-spline and re-drill existing axles which look perfect.
D)Bearings and seals

Cutting & Welding
A)spring perches dropped to bottom and moved 1.4" towards

center with same angle as 8 1/4 Or will I need to

compensate for bigger tubes?
B) flange to flange 5.1 " shorter (will be using 5.5 BS

wheels and have a good 3.5" on both sides so may not need

to shorten?)
B) 1) If I don't shorten the entire axle how do I center

it? Move the perches? Shorten one side?
C)Shorten drive shaft (Anything different with a 904 vs

727? Just swapped in the 904 fresh build with shift kit so

please tell me it's ok!)

So this is what I have so far, please help as I have time

to do this right but I don't want to do it twice, I will

spend money where I have to but am on a tight wife budget.

Cheers!

 

[crackedback]

You better measure you 8.25 because I bet it's longer than 51.40. That's from that POS chart. I'll bet it's wrong. The rear from drum to drum is about 57 1/8"

You're best bet is to put the wheels and tires up under the car and measure exactly what length you need.

Did I send you a copy of the axle lengths program? If i did, use it! From those numbers, it looks like you have it.

If you are using standard mopar drum brakes for BBP on the rear, the spreadsheet will give you the desired axle tube lengths from center section insertion point to flange. That will give you the required pinion offset. If you are using a disc brake set up, the hat thickness will change your measurements.

The bar length is the minimum length alignment bar you need to do one side at a time.

IMHO, TOTALLY disregard anything to do with the old rear axle measurements. It will do nothing but confuse you related to the desired goal. The only caveat to that, would be if you actually bolted the wheel/tire combo to the old rear and measured how far in they need to go.

BTW, if you leave the rear spring in the factory location you are limited as to how far you shorten the rear because the U-bolts will start to hit your housing ends. Looks like you have a factory 68-70 B body width 60.125, which shouldn't be an issue.

 

[Jimmy]

You better measure you 8.25 because I bet it's longer than 51.40. That's from that POS chart. I'll bet it's wrong. The rear from drum to drum is about 57 1/8"
You're best bet is to put the wheels and tires up under the car and measure exactly what length you need.
Did I send you a copy of the axle lengths program? If i did, use it! Fromthose numbers, it looks like you have it.

IMHO, TOTALLY disregard anything to do with the old rear axle measurements. It will do nothing but confuse you related to the desired goal. The only caveat to that, would be if you actually bolted the wheel/tire combo to the old rear and measured how far in they need to go.
BTW, if you leave the rear spring in the factory location you are limited as to how far you shorten the rear because the U-bolts will start to hit your housing ends. Looks like you have a factory 68-70 B body width 60.125, which shouldn't be an issue.

Actually your exactly correct (no surprise) I did measure and I found that flange to flange the 8 1/4 was the exact same length as the D60 flange to flange, give or take a half inch, I just trusted the official looking chart on moparts more than my wire i tied in knots at every interval then measured. and yes I did get the numbers from your spread sheet, (from crkd down) I was a little confused by a couple things.
8 3/4
Pass axle tube from C/L 27.46875 26.1875 2.5625 D60
Pass axle length 28.375 27.125

is this the difference between the two side if measured from the pinion center? I assume so but I didn't want to pretend to know.

if the axle is truly the same total length and I am moving the perches inboard do I really need to shorten the sides? Wont that bring the wheels closer to the inside? I don't really want that, they are already 5.5 bs and I have plenty of clearance to the fender. so the only real question is will the universal joint line up with the drive shaft if the dana is left uncut and the wheels are centered in the wells? If not how do I maintain the overall length and move the center section?

oh and the numbers were from sheet, it's a Dana 60 HD from 89 3/4 ton not sure of total length my notes are in my garage on the other side of town.

 

[crackedback]

I was a little confused by a couple things.
8 3/4
Pass axle tube from C/L 27.46875 26.1875 2.5625 D60
Pass axle length 28.375 27.125

is this the difference between the two side if measured from the pinion center? I assume so but I didn't want to pretend to know.

Correct. The first numbers are from Axle C/L as labeled, the other set is the pinion centerline with the 2.5625 being sort of a check number for the difference.

If you are doing a Dana why are you messing with the 8.75 section?

If the axle is truly the same total length and I am moving the perches inboard do I really need to shorten the sides? Wont that bring the wheels closer to the inside? I don't really want that, they are already 5.5 bs and I have plenty of clearance to the fender. so the only real question is will the universal joint line up with the drive shaft if the dana is left uncut and the wheels are centered in the wells? If not how do I maintain the overall length and move the center section?

oh and the numbers were from sheet, it's a Dana 60 HD from 89 3/4 ton not sure of total length my notes are in my garage on the other side of town.

The Dana 60 MUST have the drivers tube 1 3/8" longer than the pass side in order to get your pinion centerline in the correct location for a mopar. If you make the tubes the same length the pinion will be too far to the drivers side. Don't use the 8.75 stuff if you are working with a Dana 60.

I don't know what length of your 60hd. It's got to be long enough to get where you want or it isn't suitable.

 

[Jimmy]

Thank you again for your help, your a walking Mopar encyclopedia. I'm not sure why I was looking at 8 3/4 stuff, probably because the numbers for total length of it and the d60 on your spread sheet matched and because my 8 1/5 is the same as my Dana, also 8 1/4 info is rare at best so maybe wishful thinking, and all of the brake sizing does still apply as I ***-you-me that I cant use the drums I have now? I saw an article in a 4x4 publication where they cut a Dana too short and then welded in a tube to make up the difference, but I suppose I could just get wheels with less BS if it comes down to it. They have been the worst good deal I have gotten anyway but they did force me to buy tubular control arms for the front that are pretty sweet. I think I'll chew on this for awhile, pull the 8 1/4 and install the offset hangers and take it from there forgetting it was ever there.

Correct. The first numbers are from Axle C/L as labeled, the other set is the pinion centerline with the 2.5625 being sort of a check number for the difference.

If you are doing a Dana why are you messing with the 8.75 section?



The Dana 60 MUST have the drivers tube 1 3/8" longer than the pass side in order to get your pinion centerline in the correct location for a mopar. If you make the tubes the same length the pinion will be too far to the drivers side. Don't use the 8.75 stuff if you are working with a Dana 60.

I don't know what length of your 60hd. It's got to be long enough to get where you want or it isn't suitable.

 

[crackedback]

If you wanted to know what the Dana axle lengths are from the housing center, add 8.75 to each tube length. The 17.5 center section width is a pretty standard number. You may want to measure the center section, if it is different, input that value into the appropriate spreadsheet cell.

You can use the brakes off the 8.25 rear. They are will work fine on the Dana after the car ends are installed. The Dana spreadsheet section is set up for standard BBP standoff distances.

A quick and dirty way to find out your max rear width. Measure the drivers side tube length from center to where the end attaches. If using moser 8400 ends, add 2.25" or measure the ends you have and add that value. Input overall lengths into the spreadsheet until you hit your max drivers side tube. Make sure the pass side has at least enough material as well, usually not an issue.

 

[theclutcher]

if you are making an exact copy of what you have, I would .
1 place rear on flat surface on jacks
2 remove wheel and drums
3 drop plumb bob lines off straight edge against axle flange.
4 mark points, on floor, for and aft of axle flange to get flange line.
5 do each side.
6 drop plumb bob off center of companion flange (ujoint) or pinion nut to floor.
7 record pinion centerline dimension for left and right axles from pinion to each axle flange line.
8 give to fabricator.
If he cant figure out what you need find someone else.
9 install new axle on leafs in position desired, tack and weld perches at proper pinion angle.

get a pinion centerline tool from someone that does rear axle work or buy one from one of the companies who makes them.

 

[Jimmy]

you guys are the greatest! Ill let you know how it goes, thinking about disc brakes but if I can use the 8.25 then I can put that money towards some good axles and fab. Good Idea with the plumb lines, hard to get an accurate measurement with such a lumpy surface.

 

[theclutcher]

2X6 or plywood on top of lumps.

 

[theclutcher]

plywood on top of lumps.