I was reading an old thread regarding swapping B spindles on to the A body and being able to use big disks. If I understand this correctly I need to install 73 up upper control arms and of course ball joints to be able to use a B body spindle and breaks. This seems straight forward enough. My question is, will I have to convert to a power brake booster or can I get away with just installing a dual master cylinder? This looks like a good way to go, combined with rear discs my car would actually stop in less than 2 blocks. What was Chrysler thinking when they used 9" brakes?

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go fast, turn left, don't screw up.
WWW.Mopardropheadcoupe.com

You won't need a power brake booster. Some years had different master cylinders for power and manual discs, but this was not always the case - sometimes it was the same either way. Manual discs do produce a rock-hard pedal feel, but the discs bite so well that doesn't really matter. I am running the large B-body brakes on '73-'76 A-body spindles with no power assist.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

you don't need the b-body spindles to run the big brakes. in fact, the b spindles may be a problem. just use the 73-up abody upper arms and spindles from a disc brake car. then you can add calipers, caliper mounts and rotors from a cordoba (b-body) that has the 11 3/4 rotors.
another option is the ar engineering deal with wilwood calipers plus the 11 3/4 rotor. i looked into this for my swinger and it's a deal at under 500 bucks for everything.

-james

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I can vouch for the www.arengineering.com Wilwood/11.75" rotor setup - affordable and gives monstrously good stopping power on an A-body.

Lou

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Home of Slant6-powered fun machines since 1988

Lou,
Is your car "race only" I checked arengineerings page and it looks like the Wilwood set up is race only because there is no weather seals on the calipers, I have to drive a mile on a dirt road to get to the nearest pavement so this dosen't sound like it will work for me, also says ya gotta go with 15" wheels with the big disks. Will 15's work ok on my 66? I thought 14's was pushin' it. Any thoughts?

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go fast, turn left, don't screw up.
WWW.Mopardropheadcoupe.com

Well, it depends on how you define "work" here. If you mean physically bolting on, this is no problem. You can run considerably larger than 15" wheels on a '66 Dart. Many 17" and probably all 18" wheels even have a very interesting advantage - the top of the ball joint fits neatly inside the wheel. With a setup like that, you could run more backspacing than usual on the front (on 16" or smaller wheels, you're limited to about 4.25" of backspacing) to cram really wide tires in there. My '66 is running 16" wheels with 225/50R16 tires on all four corners. I did have to roll the inner fenders to keep them from rubbing on the fender lip up front, but they fit quite well, and narrower or shorter tires - or a higher ride height - could also prevent rubbing.

Of course, whether this looks right is another issue. You'll need fairly low profile tires to get the same diameter as stock if you go to 15" wheels - the stock 175/80R13 tires are about the same overall height as 225/50R15 tires. The look of tires with these sizes isn't at all like something you would have seen in the '60s, and my wheel and tire package is even more distorted, with lots of aluminum and very little rubber. The look is more contemporary than classic. Whether you want this look is a matter of taste, but I like the handling that goes with low profile tires.

We had quite a debate over whether the taller B-body spindles could be a problem. I was skeptical too, but we eventually had one guy show up who had done a lot of computer modeling of the suspension geometry and field tested B-body spindles on A-bodies built for hardcore handling. The results implied that the B-body spindles not only held up well, but could possibly be a performance advantage. Most of that advantage wouldn't matter on a street car or a drag car, but it could be useful for a few extra tenths of a second if you're campaigning a Street Modified autocross car.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Okay, now I'm getting excited. I am wanting to build something similar to Lou's aotocrosser. I understand from this string that I can use either my '73 A body disc spindles or B spindles with the larger B body calipers and rotors (?) If I get the larger rotors I will just need to upgrade from my 14 inch mag wheels to 15s or larger. Is this all correct understanding? Thanks,
Rob

The large style B-body rotors appeared only on '75 and later B-bodies - earlier ones used the same rotor size as '73-'76 A-bodies, more or less. They can be bolted on with either the spindles from the brake donor, or the '73-'76 A-body spindles. And this setup requires a minimum of 15" wheels.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Sorry I missed these posts earlier. The Wilwood's are technically off-road, but if you don't drive in the snow or salt, I think they will be fine. Mine have about 15k road miles and no troubles so far. Haven't had them off to check them, but I'll do that this summer. You do need 15" wheels at least. Mine are 16X8".

The 11.75" rotors are actually 77-79 B-body units - ask for '78 Cordoba rotors at the parts store. They use the same bearings as A bods too. The F,J,M,B spindles should work, although I haven't tried them - Matt is right about the calculations looking good to go.

Happy building,

Lou

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Home of Slant6-powered fun machines since 1988