Drum to disc conversion questions

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johnrobbsmusic

johnrobbsmusic

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Hello everyone, I haven't been around for a while, but now that it's summer, I'm back to working on the 67 barracuda 440/4speed project. I bought the Scarebird conversion plates for the front and have got them installed, but I'm trying to convert it to power brakes (it was manual before),
what booster/MC do I need? In the instructions that they provided, it says they would recommend a 73-75 power dart MC, in order to convert to power brakes, is there some kind of bracket that can be used to mount the booster where it needs to be? or do I just cut off the studs that the MC mounted to and drill holes to accomodate the booster?
I have an adjustable proportioning valve so I don't need a fixed one that will 'match' the setup, which leads me to my next question:
what exactly is this? I know it's a brake light switch, but is it also a propotioning valve or something? there's another a foot back on the rear line, but it's just a single in/out, is that a valve or just a smaller hole to restrict flow to the rears? do I need to leave these in? or take them off when I put the adjustable proportioning valve in?
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Thanks in advance guys, I searched around on here for an hour but could find what I was looking for in previous threads....thanks guys :)
 
That is the factory proportioning valve with the sender for the brake warning light on the dash. I would eliminate it.
 
I'm almost positive you cant have both a power brake booster and a big block. Other conflicting items like blower motor , one of the two available wiper motors. This is all from my poor memory of what I think I've read LOL Good luck with it
 
RedFish said:
I'm almost positive you cant have both a power brake booster and a big block. Other conflicting items like blower motor , one of the two available wiper motors. This is all from my poor memory of what I think I've read LOL Good luck with it
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ohhhhhh, didn't think about that, yeah, looking at some pics on google, I don't think the booster would fit...thanks :)
 
Pretty sure that's just a metering block (pressure differential switch). 4 wheel drum cars didn't use prop valves. You can use manual disc brakes easily and it won't be a problem to stop at all. I did it on mine. A power brake car doesn't stop any faster than a manual brake car. It just reduces the effort required to stop the vehicle. Your lines are looking pretty crusty, you might consider replumbing the entire system. At that point, just use your adjustable proportioning valve and you should be just fine.
 
so if I leave the metering block in, should the proportioning valve go before it, right off of the master cylinder? or after it and just run the line up where it would be accessible. I was planning on replumbing the whole thing already :)
 
johnrobbsmusic said:
so if I leave the metering block in, should the proportioning valve go before it, right off of the master cylinder? or after it and just run the line up where it would be accessible. I was planning on replumbing the whole thing already :)
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I wouldn't bother with it. If you do keep it, the prop valve has to go after it. (Remember, it's a pressure differential switch).
 
There were some small diameter, dual diaphram, boosters used from '67 to 69 that might work with your big block. The firewall bracket can be from any "A" body from 67 - 76. The factory clearanced the valve covers for this booster type and it was still a tight fit. If your going to have aftermarket valve covers you would have fitment issues even with the parts mentioned above.
 
Power brake booster will not fit with a 440. The car will stop fine with manual brakes. Get an adjustable porportioning valve (like a wilwood or summit).
 
Thanks guys, i'm going manual brakes, I've got the master cylinder froma 74 dart that had discs and I'm getting ready to run brake lines
 
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