Anyone Use 275/60-15 BFG TAs with Cragar Series 61C Cragar SS on Their Duster?

[greendart408]

My dad’s 73, 340 4spd duster he bought brand new. 15x8 w4 1/4 backspace and a factory width a body 8 3/4 with 275s

 

[72bluNblu]

Can you explain stock ride height on a 74 duster because my FSM does not it only tells how to measure it and refer to the specifications but there is no actual height measurement that I see?

The front height is set by the procedure in the FSM, there is no actual body height measurement in the FSM it's a suspension hight measurement. The suspension is set so the control arms are at a certain angle, and the resulting body height would be slightly different depending on the cars wheel/tire options.

The rear height isn't really covered in the FSM, other than using the stock leaf springs it's not really adjustable if you have all factory parts. There was a bumper height specification, you can find it here The 1970 Hamtramck Registry "Chrysler Passenger Car Bumper Heights 1965 thru 1976" Page

For a '74 A-body most of the specs are here (note this is for '74 so the Barracuda spec is E-body)

That height comes with the following conditions on how the car was loaded when it was measured

Cars that are at stock height lower have been lowered can't hang the wheels and tires out past the quarter lip, like you often see with guys running SS springs in the back. There are a couple of cars in the thread so far that you can clearly see the top corner of the 275's is outside the lip of the quarter, so their wheel specs only work if you've raised the back of the car substantially with SS springs.

 

[Chris1974]

The front height is set by the procedure in the FSM, there is no actual body height measurement in the FSM it's a suspension hight measurement. The suspension is set so the control arms are at a certain angle, and the resulting body height would be slightly different depending on the cars wheel/tire options.

The rear height isn't really covered in the FSM, other than using the stock leaf springs it's not really adjustable if you have all factory parts. There was a bumper height specification, you can find it here The 1970 Hamtramck Registry "Chrysler Passenger Car Bumper Heights 1965 thru 1976" Page

For a '74 A-body most of the specs are here (note this is for '74 so the Barracuda spec is E-body)

View attachment 1716458516

That height comes with the following conditions on how the car was loaded when it was measured

View attachment 1716458517

Cars that are at stock height lower have been lowered can't hang the wheels and tires out past the quarter lip, like you often see with guys running SS springs in the back. There are a couple of cars in the thread so far that you can clearly see the top corner of the 275's is outside the lip of the quarter, so their wheel specs only work if you've raised the back of the car substantially with SS springs.

Thanks for the reply that might get me on the right track I currently have 205 on the front and 235 on the back 14 inch rims that I got years ago for free but now im looking to get 15 inch rims and all 4 tires the same size except wider on the rear it seems like 275s would be way to tall for my current ride height. Someone else was talking about 255s is all he uses.

 

[TimS]

I'm glad I bought the 255's. No issues on back with the 8 1/4 rear and mounted on 61C 15X8 Cragars. Now going to get rid of these 205/60's.
Look like they belong on a Fiat.

215-65/15's T/A's should look better.

 

[QuickDart360]

I'm glad I bought the 255's. No issues on back with the 8 1/4 rear and mounted on 61C 15X8 Cragars. Now going to get rid of these 205/60's.
Look like they belong on a Fiat.

215-65/15's T/A's should look better.

Do you happen to know whst backspace your 15x8's are? I too have an 8.25 rear. However, my car is a dodge dart sport. I currently have 15x7 rally wheels and they are close on the inner side. I really want to go 15x8 ro 15x10. But not sure if they will fit without rubbing.

 

[TimS]

Do you happen to know whst backspace your 15x8's are? I too have an 8.25 rear. However, my car is a dodge dart sport. I currently have 15x7 rally wheels and they are close on the inner side. I really want to go 15x8 ro 15x10. But not sure if they will fit without rubbing.

The wheels I'm using are 61C Cragar with a backspace of 4.25"

 

[TimS]

My dad’s 73, 340 4spd duster he bought brand new. 15x8 w4 1/4 backspace and a factory width a body 8 3/4 with 275s

View attachment 1716457978

Nice 73!! What size tires does your dad run on the front of his Dart?

 

[greendart408]

Nice 73!! What size tires does your dad run on the front of his Dart?

Thank you, it’s really nice. Front tire size is 155/80 on a 15x4.5 wheel

 

[Bullet]

I've never had issues with 275's on 8 3/4 rears and 4.25 backspace wheels but this 74 is a different animal. Like you said, this 74 has a good sized inside lip on the qtr. I know 275's won't clear the outer lip but what about the leaf springs from the inner perspective? Thanks !!

Is a 73 basically the same, or is that unique for the 74?

 

[72bluNblu]

Is a 73 basically the same, or is that unique for the 74?

Dusters all the same as far as the wheel tubs, quarter lips and spring locations go. You can get 275’s on a ‘74 with no issues at all, or a 73, or a ‘70.

There is a difference in the backspace needed depending on which rear axle and what bolt pattern the car has. 70-72 could have 8 3/4’s (SBP) and they are wider than the 7.25 and 8.25 rear ends used 73+. The 73+ cars could also have been large bolt pattern from the factory, where 70-72 would have all been SBP regardless of the rear axle.

But yeah, Dusters, Demons, Dart Sports all have the same inner and outer wheel tubs, quarter lip, and spring location ‘70-76. There is car to car variation because of build tolerances, but not a year to year difference in those dimensions.

 

[Bullet]

Dusters all the same as far as the wheel tubs, quarter lips and spring locations go. You can get 275’s on a ‘74 with no issues at all, or a 73, or a ‘70.

There is a difference in the backspace needed depending on which rear axle and what bolt pattern the car has. 70-72 could have 8 3/4’s (SBP) and they are wider than the 7.25 and 8.25 rear ends used 73+. The 73+ cars could also have been large bolt pattern from the factory, where 70-72 would have all been SBP regardless of the rear axle.

But yeah, Dusters, Demons, Dart Sports all have the same inner and outer wheel tubs, quarter lip, and spring location ‘70-76. There is car to car variation because of build tolerances, but not a year to year difference in those dimensions.

Awesome!! Thank you for breaking it down for me.
I have a 73 Duster and I wasn’t sure how wide I could go in the rear.

 

[Bullet]

We are installing a 71 340 block in my 1973 Duster. We are having a very hard time locating a driver’s side motor mount which is pretty unique.
Any idea where I can find this motor mount?
Thank you in advance.

 

[72bluNblu]

We are installing a 71 340 block in my 1973 Duster. We are having a very hard time locating a driver’s side motor mount which is pretty unique.
Any idea where I can find this motor mount?
Thank you in advance.

I think Schumacher is the only one that makes them, they appear to be sold out '73+ A,B,C,F,M,J-Body 273/318 or 340/360 Replacement Kit

The 318 mounts work, you just need to add a spacer between the ear on the block and the mount because the mount is wider on the 318. I suppose you could also split the 318 mount, removed the 1/2" or so of extra width and weld it back together if you were so inclined.

 

[Bullet]

I think Schumacher is the only one that makes them, they appear to be sold out '73+ A,B,C,F,M,J-Body 273/318 or 340/360 Replacement Kit

The 318 mounts work, you just need to add a spacer between the ear on the block and the mount because the mount is wider on the 318. I suppose you could also split the 318 mount, removed the 1/2" or so of extra width and weld it back together if you were so inclined.

Thank you for the info, much appreciated! This is my first Mopar so, lots to learn!