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Keep in mind that any kit that uses Granada rotors will widen the track about 1" (1/2" per side). The Camaro rotors may do the same, but I have never used them.

There are some kits that use custom hubs and separate rotors that don't change the track as much. I have a Baer kit on my current project that only adds 1/4" to each side.

Check tire clearance to the fenders well to make sure you don't run into trouble.
 

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Discussion Starter · #42 ·
Keep in mind that any kit that uses Granada rotors will widen the track about 1" (1/2" per side). The Camaro rotors may do the same, but I have never used them.

There are some kits that use custom hubs and separate rotors that don't change the track as much. I have a Baer kit on my current project that only adds 1/4" to each side.

Check tire clearance to the fenders well to make sure you don't run into trouble.
Only had my car a couple of weeks and haven't had the wheels (5 lug 17" mags) off yet, but I assume if the 9" brakes are not aftermarket that I have wheel adapters to go from 4 to 5 lug, which should make the track similar to Granada rotors. Correct?
 

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Discussion Starter · #43 ·
Keep in mind that any kit that uses Granada rotors will widen the track about 1" (1/2" per side). The Camaro rotors may do the same, but I have never used them.

There are some kits that use custom hubs and separate rotors that don't change the track as much. I have a Baer kit on my current project that only adds 1/4" to each side.

Check tire clearance to the fenders well to make sure you don't run into trouble.
Only had my car a couple of weeks and haven't had the wheels (5 lug 17" mags) off yet, but I assume if the 9" brakes are not aftermarket that I have wheel adapters to go from 4 to 5 lug, which should make the track similar to Granada rotors. Correct?
 

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You might even be narrower when you lose the adapters. Should be close. If you are narrower, a thin spacer will get you back to where you are now.

Be sure to check bolt pattern on your current wheels before deciding a brake kit.
 

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On my Pontiac the front track width was about 3 narrower than the Camaro rear track (some of that was the tires, 235 vs 215), and I had plenty of clearance inside the fenders for the wider front track. Mine had GM pattern 9" rotors when I got it, didn't have any worries about spacers/adapters.
 

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Discussion Starter · #46 · (Edited)
On my Pontiac the front track width was about 3 narrower than the Camaro rear track (some of that was the tires, 235 vs 215), and I had plenty of clearance inside the fenders for the wider front track. Mine had GM pattern 9" rotors when I got it, didn't have any worries about spacers/adapters.
Bob, I have a question for you or anyone else familiar with stock 9" brakes on large street rods (say 3500 lbs plus). I would expect lackluster performance since they were designed for a Pinto, but mine seem worse than that- stepping on them is very similar to a mechanical brake system, not remotely capable of a panic stop, "stomp and pray" . The only car I've owned with brakes this bad was a 1919 Chevy. I'm wondering if something else is wrong with mine. I have jacked up the wheels and confirmed they all are working. Also confirmed that my brake booster is operational.

As far as the track goes, checked today and found the rotors have 1" wheel adapters and front track is narrower than back, so any widening of the track by a new disc system, won't be an issue.
 

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My braking issue started with the booster that was on the car went bad. It was reputed to be from the same '74 donoor that the front clip came from. There is only one booster offered for '75-78 MII, and it didn't match up with what I had.

I went with an after market 7" dual diaphragm booster, dual MC with proportioning valve combo (brand new) I got from a friend. After mounting and making adjustments to get a straight push from the pedal to the booster, I had better brakes, but they still seemed a bit weak. That's when I went for the 11's. Better, but still not quite right!

Finally figured out the proportioning valve was for 4 wheel discs instead of disc front/drum rear. Changed that out and now have proper braking.

Might possibly been OK with the original 9" discs, but like cubic inches, you can't go wrong with more brake power!
 

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Discussion Starter · #48 ·
My braking issue started with the booster that was on the car went bad. It was reputed to be from the same '74 donoor that the front clip came from. There is only one booster offered for '75-78 MII, and it didn't match up with what I had.

I went with an after market 7" dual diaphragm booster, dual MC with proportioning valve combo (brand new) I got from a friend. After mounting and making adjustments to get a straight push from the pedal to the booster, I had better brakes, but they still seemed a bit weak. That's when I went for the 11's. Better, but still not quite right!

Finally figured out the proportioning valve was for 4 wheel discs instead of disc front/drum rear. Changed that out and now have proper braking.

Might possibly been OK with the original 9" discs, but like cubic inches, you can't go wrong with more brake power!
Do you recognize this booster? I think it's working but not that well. Also, I could well have the same proportioning valve issue, will need to check mine and see what I have.
 

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