1. Lennybody

    Lennybody Member

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    I am considering a 4 wheel disc brake set-up. A PST kit states their kit converts SBP to LBP. This seems reasonable for the front (rototrs with LBP studs) however the don't the rear rotors install on the studs, so I believe that this would require changing the axles to a LBP, right?
     
  2. jrcr_15

    jrcr_15 Well-Known Member

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    Yes that is correct. Sbp axels have a 4" bolt pattern and the lbp are 4.5" bolt pattern. Unless you bought some kind of adapter, you will likely need to swap the rear axels too
     
  3. Lennybody

    Lennybody Member

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  4. Lennybody

    Lennybody Member

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    Did a bit more searching, thanks to this forum. I am leaning toward Dr. Diff 11" front discs LBP a pair of LBP axles. (perhaps power brake booster and rear discs)
    Goal for 67 Cuda notchback- goofing off driver/hotrod decent 273 (maybe upgrade to a larger smallblock for perhaps 400 HP).
    Should I go 4 wheel power disc brakes?
    Should I stick with manual front disc brakes and rear drums?
     
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    • Lennybody

      Lennybody Member

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      Thank you for confirming. I was upgrading the car quite a bit over 20 years ago. Then life got in the way and she has pretty much sat around since. My previous conversion to K-H front discs was based on keeping the SBP. Now those K-H brakes are seized up, I may rebuild them but decided to look into BBP. Of course that will require new wheels.....
       
    • nitro_rat

      nitro_rat FABO Gold Member FABO Gold Member

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      Manual front disc/rear drum is my favorite setup. Don't forget the proportioning valve...
       
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      • kursplat

        kursplat FABO Gold Member FABO Gold Member

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        power brakes is a personal preference. i've been taking the power boosters out for over 30 years
         
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        • AJ/FormS

          AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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          Wait what? a 400hp 273? Whoa.....
          I'm guessing that will not be Normally Aspirated.
          But if it was, that would take a lotta rpm so not much torque involved. And sooner or later you will be looking at putting some decent tires under that notchie, which will lead to a narrowed rear end. So IMO, you might as well start there.
          But if not and this is gonna be a street car, I see no reason for discs on the back. The 10x2s are already too powerful for 275s, and you will have to reduce the line-pressure.
          I have a 68FB with a 367HO in it, 430hp by the trap in the 1/8th, and after I put the 295s under it, I gutted the P-valve, and gave her full pressure at the back on 7/8 "wc's IIRC, and 10x2 drums. I used the KH'ers on the front with a 15/16 M/C and a booster from a 73 Dart IIRC. Also some braided front lines. After some testing I found this set up pretty awesome for my streeter. It had no trouble hauling me down from 93 in the Eighth, to ~30, for the pit road.
          The thing is, my 367 makes plenty of vacuum,with just a 230* cam, and is a clutch-car; so it easily runs the booster.
          I suspect a 400hp NA 273 will not have much vacuum, so you might as well leave the booster on the bench;...... unless your notchie too ,will have a clutch, with like 4.88s or something,lol.

          Contrary to literature of the day, you can machine the rotors with modern equipment.and
          You can pump the pistons out of the calipers little by little on the car, or with a grease-gun, using C-clamps to prevent the movers from popping out early.
          I installed silicon brake fluid in 1999, and my calipers are still working just fine.
          Yes; I run the Sbp on the front, and the Bbp on the back, Big N Littles, just like back in the day; and no spare. In 20 years I have had one tire go down on me, just 3 miles from home. Unfortunately it was the only time my wife was ever with me. I stuck out my thumb, and within minutes we were home. Then I grabbed an air tank and off I went. For me, not having a spare is no big deal. A flat tire is just an opportunity to meet a good Samaritan.
           
          Last edited: Jun 29, 2020
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          • Lennybody

            Lennybody Member

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          • Lennybody

            Lennybody Member

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            Lol, no if I upgrade the engine it will be a swap to a 360 or 408 to easily get the HP and torque. The bigger brakes (possibly Dr Diff Stage 3 set-up) would be for handling and braking. I am thinking P225/45R17 front and P245/40R17 rear. I think that I will give Dr Diff a call to discuss the set-up. I have seen quite a bit of stuff on this forum that he is a straight shooter.
            The car is a column shift auto but a stick would be nice one my first cars was a 72 Challenger Rallye 340 with Pistol Grip. Feel bad that I trashed that car 40 years ago (was a lot of fun though).
             
          • AJ/FormS

            AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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            Yeah, I had no idea my 1970 Swinger 340/4speed/PantherPink, would someday be desireable. I drove that car to death in 4 summers. IIRC, it was on it's second engine, third trans rebuild, third rearend, seventh set of rear tires, and Ima thinking third clutch. It had been to the bodyshop twice, and I doubt there was one straight panel left on it when I sold it, in Feb 1975, having purchased it in fall of 1970,used with 11,000 miles on the clock.. The cops knew my car so well, they would come aknocking on Mum's door everytime some punk was reported to be misbehaving in the neighborhood.I mean,what was I thinking! You can't mistake a Pink car!, never mind a Pink Dart. In the few years I owned it, I never saw another pink car in Winnipeg, and only one since; a repainted Pink Duster, in about year 2002.
            Those were the days...........
            _______________________

            I got just one piece of advice, as always, in story-form;
            245s and 408 should not be said in the same story, with the word handling.
            Even a sucked out 4bbl smogger-teen318 spins out regularly with those. Just a bit too much gas and there you are again,pointing backwards in traffic, usually on the inside median. I'm not kidding. Now I suppose there are stickier 245s out there than what I had, but I mean how much better can you get! It's still just a 245.
            With my 367, I went to 255s, 275s, then 295s, to finally not have that problem anymore. Plus all the regular stuff like 1.03 bars, a big swaybar, HD shocks, all new suspension and steering,etc.
            To put the 295s in there on the 4.5backspace period kidney slot 15x10s, I had to narrow the rear and move the springs inboard. That was the best decision I ever made to the chassis.
            The thing is this; when you're sliding sideways, the rear brakes don't work, and the fronts become pivot points for the car, and you are in a 360 spinout and there is nothing you can do except hold-on for the ride.

            So here comes the advice ; in two parts, for a streeter; and does not apply to a competition car.
            Part 1)
            I don't think you can do anything, I mean anything, to marry a 408 to 245 rear street tires, and not create a huge handling nightmare. So firstly; a 360HO is more than adequate, and 295s are barely adequate for the 360.
            Part 2)
            A) Sooner or later, if you don't start with big fat street tires, you will end up there.............. so you might as well just start there and save yourself the cost of the learning curve.
            B) At street-legal speeds, 10" drums even, are adequate stoppers, and they are self-energizing so don't need a booster.
            C) If using a 360, make it high-compression and use a 223 to 230 degree cam, and you will have torque up the wazoo. I highly recommend a double-pumper and a manual trans for the predictability,consistency, and repeatability; read safety, that those bring to the party.
            D) with the above three points in mind,
            if I was on a budget,
            I would put off aftermarket brakes, until the stinking car goes where you point it, every time, and if it doesn't, that you can at least steer it back to a safe line.
            I have mine set up so that in mid turn, with the rear tires smoking, that if it oversteers, I back off the gas and it stops sliding just about instantly. Yeah the car sometimes lurches weirdly and passengers get sore necks, but we(I) didn't crash or wipe out!, so it's all good. IMO, that is what you want; namely instant recovery.
            The truth is, I rarely need to use my brakes, because I rarely get into trouble, because the car is more predictable than I am,lol. Because of this, I sometimes drive harder,faster, deeper, more crazy probably than I aught to, and it's getting harder to find passengers,lol. Itsok, I'm fine by myself.
            E) also worth mentioning, is that with big tires in the back, you can increase braking back there, where a streeter, well OK, my streeter, can really use it. The manufacturer has set your car up with a proportioning system, that prevents the rear brakes from doing almost any braking at all. It makes it safe for them, knowing the system will not cause you to spin out in mid turn if you happen to need to step on the brake pedal.
            But those brakes are set up for skinny D78-14 tires. That's about 185s IIRC. Now,with 295s, and 10x2 rear drums, you can get rid of the P-valve and run 100% line pressure to the back, and do your "proportioning" with wheel-cylinder size. I use 15/16 back there with the KH 4-piston fronts. . With that, the manual trans/ 11:1 compression engine, and a carb that closes, my brakes lack nothing.
            E) another thing worth mentioning is that on the front, you will be hard pressed to fit more than 235s. And that is gonna set the tone for the front brakes. Again; even the 10x2.5 factory drums can handle all your street-legal braking needs. Disc brakes are nice in competition because you can change pads in minutes. And disc brakes have better fade-resistance for competition. But otherwise for a streeter,with 235 street tires, I fail to see any need for aftermarket big disc brakes. I always like to say something like ; why do you need a cannon to shoot a squirrel, when a slingshot will make him just as dead; how dead do you need it to be? Locking up the front brakes at 60 mph, might be interesting, but totally not required, nor even desirable, on account of if the tires are skidding, you cannot steer. If the rears are also skidding; in a heartbeat the back will be in the front, and in whatever direction you are traveling, that is the direction that the car will continue to travel, until acted upon by a greater force, or it stops; not lol. So once again; the front tires are the brake limiters. I see no practical advantage to having 100mph brakes on 40mph tires.
            Ok enough talking; except
            if not on a budget,
            drive on; but easy on the panic braking, lol.
             
            Last edited: Jul 1, 2020 at 8:54 AM
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            • Lennybody

              Lennybody Member

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            • Lennybody

              Lennybody Member

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              AJ,

              Thank you for the advice is your 367HO a 0.30 over 360 or 360 magnum?
               
            • AJ/FormS

              AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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              4.04bore LA, 1971 born 360
               
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