SBP to Big Bolt Conversion

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Indiges

Indiges

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Sorry, this has probably been asked to death but I couldn't find an answer through searching.

If I converted my fronts to 73+ components to get the BBP, would the existing calipers fit or would I need to upgrade these as well?
 
Nothing interchanges except the lower control arm. Everything else is removed and replaced.
 
I'm assuming you already have discs, but they're the early Kelsey/Hayes with the small bolt pattern? If they are working well and you're satisfied with them, and are only looking to get the big bolt pattern, consider keeping them and just replacing the rotors with early Mustang (yeah, I know) K/H rotors that have the 4.5 bolt pattern. There's a different inner bearing and seal to use if memory serves me, but a quick search should turn up the info you need. Much cheaper and easier than swapping over the whole system.
 
Thanks for that. I was hoping to keep them so this is really useful.
Professor Fate said:
I'm assuming you already have discs, but they're the early Kelsey/Hayes with the small bolt pattern? If they are working well and you're satisfied with them, and are only looking to get the big bolt pattern, consider keeping them and just replacing the rotors with early Mustang (yeah, I know) K/H rotors that have the 4.5 bolt pattern. There's a different inner bearing and seal to use if memory serves me, but a quick search should turn up the info you need. Much cheaper and easier than swapping over the whole system.
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DR Diferential is only 11' and Pirate Jack is 12'' pirate jack is MBM brakes all Quality parts delivered for $650 and Dr Differentials is almost $1000 delivered.I did my homework before I bought mine. I am very happy with Pirate Jacks (MBM) brake kit.
 
There is a sticky at the top of this forum about using the Mustang rotors. Some machining required.
 
maddawg57 said:
DR Diferential is only 11' and Pirate Jack is 12'' pirate jack is MBM brakes all Quality parts delivered for $650 and Dr Differentials is almost $1000 delivered.I did my homework before I bought mine. I am very happy with Pirate Jacks (MBM) brake kit.
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No such thing. Did you actually measure them? Because I'd almost guarantee those are just reproduction Mopar 11.75" rotors. They use the same 73+ spindles, the same calipers, and the same caliper brackets. Just false advertising. They also don't use Timken bearings or seals. And who knows what you're getting for ball joints or hardware. There are several threads about the MBM/Piratejack rotors having out of round issues.

DoctorDiff sells the 11.75" kit too. You get all Timken bearings, and actual quality parts. You get far better customer service. I priced out everything in that link, it comes to $780 from DoctorDiff, but that also includes the tapered spindle adaptors ($35). Yes, shipping would be on top of that. High quality bearings and real customer service make up any difference in price by far.

Mopar 11.75" Front Disc Brake Kit (Stage 2)
 
72bluNblu said:
No such thing. Did you actually measure them? Because I'd almost guarantee those are just reproduction Mopar 11.75" rotors. They use the same 73+ spindles, the same calipers, and the same caliper brackets. Just false advertising. They also don't use Timken bearings or seals. And who knows what you're getting for ball joints or hardware. There are several threads about the MBM/Piratejack rotors having out of round issues.

DoctorDiff sells the 11.75" kit too. You get all Timken bearings, and actual quality parts. You get far better customer service. I priced out everything in that link, it comes to $780 from DoctorDiff, but that also includes the tapered spindle adaptors ($35). Yes, shipping would be on top of that. High quality bearings and real customer service make up any difference in price by far.

Mopar 11.75" Front Disc Brake Kit (Stage 2)
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Well I got great customer service and am very pleased with what i got. Your first link you posted were for the 10.96'' (11")The adapters were included in my kit as well i posted the adapters in case he was using used b body parts and didn't want to change upper CA. My ball joints were MOOG . And yes they are 11.75" rotors cross drilled , slotted and cadmium coated ,which is called 12''. $300 difference and I am happy . He can buy what he wants and you can to . I just put the info out there. There is also the RAM MAN but he is even higher. Have a great day.
 
maddawg57 said:
Well I got great customer service and am very pleased with what i got. Your first link you posted were for the 10.96'' (11")The adapters were included in my kit as well i posted the adapters in case he was using used b body parts and didn't want to change upper CA. My ball joints were MOOG . And yes they are 11.75" rotors cross drilled , slotted and cadmium coated ,which is called 12''. $300 difference and I am happy . He can buy what he wants and you can to . I just put the info out there. There is also the RAM MAN but he is even higher. Have a great day.
Click to expand...

The OP was originally talking about keeping his KH calipers, so, I assumed he wasn't looking for an upgrade to 11.75" rotors. He also didn't mention whether he has 14" or 15" wheels, and the 11.75's require 15's. PirateJack also sells the smaller 11" kit.

The fact that PirateJack/MBM calls that kit a 12" kit is straight up false advertising. 11.75" is not 12". And it's not anything special either, it is literally 100% reproduction Mopar parts. Not that long ago you could get everything you needed for that conversion from a junk yard, all you needed was a '76-'81 B or R body. Advertising it as a 12" kit just confuses people, they think they're getting something other than OE parts. It's just a cheap reproduction.

As far as quality, you can check this thread where two different members talk about how their PirateJack/MBM rotors were out of round on the hub to the point that there was caliper interference. One even asked for a replacement and got one that was further out than the original one. No thanks. There are others too, this is just the easiest one to find. Ordered My Disc Brake Conversion Kit

Yes, the OP can do what he wants. And given that he's in New Zealand he probably won't be using DoctorDiff. Nothing wrong with that, but I definitely wouldn't recommend PirateJack/MBM. Yeah, I'm ok with spending some more money to get quality parts and a real human being that can answer technical questions about these cars. I've done business with DoctorDiff for years, he's a class act and uses the best parts available. That's worth something.
 
Hi all,

I appreciate all of your input. I now have a lot clearer idea of what direction I will be going with.

Yes, I am in NZ, but the car is currently in Mexico and will be rebuilt there, so US sourced parts and suppliers are welcomed.
At this stage, I will be trying to keep it as original as possible, so, will look at sourcing the Mustang discs so I can run the existing calipers as Professor Fate recommended. I found the link on how to do this:

Using mustang rotors for 4.5" bc

The reason is that when I eventually import the car back, the compliance process is very strict, so I have just learned, so keeping it looking as original as possible, makes this process a lot easier.

Once I have gotten through compliance, I will look to upgrade to something after market.

Thanks again for all of your input, it has been invaluable.
 
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