8 3/4 bbp on my 67 dart

[illrad91]

I got a 8 3/4 rear all setup the housing was cut for a body specs but since ive put everything together like disc and 4 link it seems to hit the inner fender on one side. Am I missing something. They are about 9inch tires in back idk what size exactly. Could someone send me pictures of there's by chance snd what they did for clearance. Sorry for all the rags its about to rain so im trying to cover it all up.

 

[junkyardhero]

my 68 dart is the same way-- a little tighter on the one side than the other. it's just production tolerances from when they're built.

1- 245's is about as big as you can go with "production/factory" parts-- ie stock a-body 8.75, big bolt brakes, 7" rim with 4.25 BS
2- the offset of BBP axles and discs add to the width. if you didn't account for this then that would likely be the difference and why you're having fitment issues.

possible remedies:
>roll the wheel lips, maybe push the sheet metal out a hair
>smaller tires
>rims with more offset
>reset/reposition the axle

 

[illrad91]

my 68 dart is the same way-- a little tighter on the one side than the other. it's just production tolerances from when they're built.

1- 245's is about as big as you can go with "production/factory" parts-- ie stock a-body 8.75, big bolt brakes, 7" rim with 4.25 BS
2- the offset of BBP axles and discs add to the width. if you didn't account for this then that would likely be the difference and why you're having fitment issues.

possible remedies:
>roll the wheel lips, maybe push the sheet metal out a hair
>smaller tires
>rims with more offset
>reset/reposition the axle

Great thank you so much for the info yea ill guy try the fender roll maybe first if not ill just get other tires. Yea i didnt take the disc bbp into consideration i remember i got the rims for like 50 bucks so i didnt really care. I really liked these but its way to close to the fender for me. Sorry for the dumb question but what did you mean by 4.25 bs? Aren't the bolt pattern 5x4/5?

 

[junkyardhero]

Great thank you so much for the info yea ill guy try the fender roll maybe first if not ill just get other tires. I really liked these but its way to close to the fender for me

fwiw, on the 68 dart i have a stock a-body 8.75 with big bolt dutchman axles and 11X3 brakes, the rims are factory 15X6.5 w/ 4.25 back space and i'm running 235/60 cooper cobras and they just-t-t-t fit. the passenger side is *slightly* tighter than the driver's side.

 

[Oldmanmopar]

Loosen everything up. all 8 nuts on the Front Hanger. all 4 on the rear hangers. Then all the u-bolts. Let it hang with no shocks fastened , Push the rear over to center it and tighten the front hanger bolts first then the rear hanger bolt. Then let the rear hang again and check center. If it moves when tightening the u-bolts you may have to hold it past center when tightening the hangers and try again.

Some of the 6 cylinder and 318 automatic bodies , many are made crooked and require shims in front of the front hangers, A quick check is looking at the piece that the front hanger is bolted to.. There is a hole in the bottom of the frame rail . measure the distance from the hole to the brace the spring fastens to. Many time the left side is front farther by 3/8 of an inch . Shim the right side back. Just something to check.

I see many 6 cyl. cars made to race cars in the water box at the track where they have to be held straight doing a burn out this is usually why. The exact way to correct this is measurements off the K member but for a street car this is a quick way.

 

[RedFish]

Knowing the driveline is offset and not down the center of the body,,, get a pencil and draw a capital I on its side but skew it's center line like the driveline. You should see that the short line representing the rear axle needs to be shifted toward square to prevent severe dog trot. There isn't a difference in length of doors, fenders, side to side. Thus tires in the wells are not the same side to side.
So it's not just your A-body or some A-bodies but all of them.

 

[illrad91]

my 68 dart is the same way-- a little tighter on the one side than the other. it's just production tolerances from when they're built.

1- 245's is about as big as you can go with "production/factory" parts-- ie stock a-body 8.75, big bolt brakes, 7" rim with 4.25 BS
2- the offset of BBP axles and discs add to the width. if you didn't account for this then that would likely be the difference and why you're having fitment issues.

possible remedies:
>roll the wheel lips, maybe push the sheet metal out a hair
>smaller tires
>rims with more offset
>reset/reposition the axle

Knowing the driveline is offset and not down the center of the body,,, get a pencil and draw a capital I on its side but skew it's center line like the driveline. You should see that the short line representing the rear axle needs to be shifted toward square to prevent severe dog trot. There isn't a difference in length of doors, fenders, side to side. Thus tires in the wells are not the same side to side.
So it's not just your A-body or some A-bodies but all of them.

Im gonna be completely honest I somewhat dont understand what you said would you mind elaborating please? Thanks regardless

 

[junkyardhero]

Sorry for the dumb question but what did you mean by 4.25 bs? Aren't the bolt pattern 5x4/5?

BS= back spacing of the rim. or what a lot of people refer to as "offset".

basically from the where the wheel mounts to the axle flange to the outer lip.

(it's a little more granular than that but that's the basics)

 

[jos51700]

BS= back spacing of the rim. or what a lot of people refer to as "offset".

basically from the where the wheel mounts to the axle flange to the outer lip.

(it's a little more granular than that but that's the basics)

This.
OP, read up on backspacing, there's actually a lot there to digest.

 

[RedFish]

Im gonna be completely honest I somewhat dont understand what you said would you mind elaborating please? Thanks regardless

From engineering standpoint there must be like 7 degrees offset in a driveline that includes universal joints.
I'll be honest too. I know a litlke more today than i ever understood completely.
Your engine isn't in the center of the engine bay.
The trans tunnel isn't in the center of the floor pan. Driveshaft meets differential at an angle.
How did they make this 4 wheeler track anywhere near straight?
Go measuring around and you'll find some clues.

 

[illrad91]

From engineering standpoint there must be like 7 degrees offset in a driveline that includes universal joints.
I'll be honest too. I know a litlke more today than i ever understood completely.
Your engine isn't in the center of the engine bay.
The trans tunnel isn't in the center of the floor pan. Driveshaft meets differential at an angle.
How did they make this 4 wheeler track anywhere near straight?
Go measuring around and you'll find some clues.

Seriously I didn't know any of that. But my driveshaft isn't connected yet I needed to get my rearend properly before I did any of that

 

[RedFish]

Seriously I didn't know any of that. But my driveshaft isn't connected yet I needed to get my rearend properly before I did any of that

I understand. Others have suggested ways to alter what your oversized tires have revealed. I only attempted to shed a little light in why it is the way it is and that yours is not different from all others. Happy moparing