8.75 rear vent position

[bbscamp]

I've got two 8.75 housings for my E.   both measure the same length and perch spacing.  the flange area on the tube looks a little different.....but the internal measurements are the same.  the question:  one has the rear brake line block / vent hole 7 " from the center of the pig ( on the sloping should between the rear and tube) and the other is 10.5 " from the center (on the axle tube round section).  Which is the right housing for 1970??  thnx

[Challenger6pak]

You will use the one that has the roughly 7 " measurement.  That is what is on my 70.  My 73 has the 10" measurement.

[bbscamp]

here is the two rears.....top shows the difference in vent positions.  the second show a difference in the tube end.  Inside dims at the flanges are the same.    The one with the 10+" vent dim has the wider outside collar on the tube by the flange.  My guess is it looks stronger. 

[Challenger6pak]

When looking at my 2 cars (70 & 73)  I can see the rear brake hose comes in from a different location.  I believe this is because the emergency brake cables were moved from 1 side (like b-bodys) 70, to 2 sides, 71-74. This new routing caused Chrysler to move the mounting hole, also the vent hole, over a few inches.

[bbscamp]

what do the collars look like by the flange?    the 10 incher has the smaller collar....the 7 incher the wider collars by the flange......

[Challenger6pak]

I don't know.  The cars are packed tight together.  I was able to get under the rears to measure for you.  I can't tell about the ends due to the fact they are completely assembled.  I do know the 7" is the right one for '70.

[bbscamp]

I was trying to look closely at the rear hose mount and flange size for this 70 Chally RT resto:   http://www.ridesthatrock.com/html/disc_brakes.html    It looks like the rear housing has the vent hole on the tube (10" one) and the wider, 2" collars.           I have a 7 1/4 under the S6 chally...I"m going to look at the position of that one.

I do believe you that the 7" (on the shoulder vent) is for the 70.......maybe both were used in 70??    But it WILL make a difference if I buy prebent brake lines!!!   so I gotta make sure!

[Challenger6pak]

I do not think it will make any difference on your prebent lines.  Is there separate part number for 70 on aftermarket lines?  It is possible both rears were used in 70.  I have been fortunate enough to have the original equipment in my cars that I could keep in them.  Maybe someone else has come across this.  The only difference I could see would be with the rear brake hose position.  I do know the 70 is a different hose.  Does the 71 up version fit the 70?  I have never tried it.  Most parts houses sell the 71 up version as fitting all Challengers.  I have used the 70 Charger rear brake hose as a replacement in my 70 Challenger.

[Alaskan_TA]

My '70 challenger housing has the 10" vent mounting position and the wide flange collars.

Barry

[Challenger6pak]

My guess it that Chrysler used 2 suppliers for the rear end parts and it does not really matter.  I went through the 1970 service bulletins I have and there wasn't any mention of changing the rear end housing due to problems.

[bbscamp]

Side by side, the two have a different pinion angle too!   One is probably twice the other!  I'll need to measure them to be sure.  What is the correct pinion angle??? 

[Chryco Psycho]

5-7* nose down is correct