1973 slant six sbp or bbp?

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Fuzz

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Hi all! Got a 73 Duster that was originally a slant 6 with front disks as a donor car for my 1972 Duster. I was wondering if the slant 6 with disk was only small bolt pattern?

I read that anything 1973 and up was bbp so I picked up the parts car but it's looking like I may be wrong.

Thanks in advance!
 
Easy way to tell. Are they 4 piston Kelsey Hayes or single piston?
The only SBP A body discs were K-H.

But 45 years later a lot of these cars are mongrels.
 
I believe in 73, disc brake cars were LBP. Small bolt pattern still came on some/most/all/a few drum brake cars. But never say 'all' or 'always' on the first year of a change.
 
Since it was a /6 car, I'm guessing the fronts were originally drums and a 5x4 bolt pattern that was at some point converted to a K H dual piston caliper. According to the literature, the 1973 318 cars and above came standard with the new single piston disc brakes and 5x4.5 bolt pattern.
 
Easy way to tell. Are they 4 piston Kelsey Hayes or single piston?
The only SBP A body discs were K-H.

But 45 years later a lot of these cars are mongrels.
Single piston! I'm not by the car right now so I can't measure it myself but i just wanted to verify as I'm new to this kinda thing.
 
Since it was a /6 car, I'm guessing the fronts were originally drums and a 5x4 bolt pattern that was at some point converted to a K H dual piston caliper. According to the literature, the 1973 318 cars and above came standard with the new single piston disc brakes and 5x4.5 bolt pattern.
It's stock power disk brakes actually!
 
I believe in 73, disc brake cars were LBP. Small bolt pattern still came on some/most/all/a few drum brake cars. But never say 'all' or 'always' on the first year of a change.
Was there a lot of mismatching of parts during the first year of the change?
 
Single piston! I'm not by the car right now so I can't measure it myself but i just wanted to verify as I'm new to this kinda thing.

Was there a lot of mismatching of parts during the first year of the change?

If it's a single piston caliper then it's the later 73+ disks and it's 5x4.5". There was not a lot of "mismatching of parts", and regardless all the factory single piston calipers were part of the BBP disk set up.

In 1973 the disk brakes changed from the SBP Kelsey Hayes disks to the single piston BBP disks. The upper control arms also changed to accommodate the larger ball joints that were used. Basically the A-body cars went to using the same brakes and ball joints as the other model lines. The 1973+ V8 cars came with disk brakes standard, so they were all BBP. The slant-6 cars still came with 4 wheel drums standard, and the 4 wheel drum cars were still SBP (but got the larger ball joint UCA's still). But, disk brakes were an option on the slant 6 cars, and if they got disks they were BBP. And some of the other options triggered the disk brake option too, like a towing package, so quite a few /6 cars ended up with disk brakes and the 5x4.5" pattern.
 
8.25 rear meant disc front from 73 up, no matter engine. There wasnt an A body small bolt pattern 8.25.

4 wheel small bolt pattern drums were used until 12/31/75 when Feds req'd front disc brakes for 1/1/76 production.
 
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