One last one, again. Is the disc brake upper control arm from an A body the only one that will work? I haven't torn my Dart apart to verify stud diameter, but the ball joint socket I have fits both the disc brake set up and the 10" drum set up. Is it niaive to think that I could use upper control arms from a 10" brake A body with ball joints that would fit a disc brake car? Thanks again.
Rob

The upper A-frame / upper ball joint size is larger for the 73 and later large bolt pattern (5 on 4 1/2 LBP) Disc Brake set-up.

If you convert to the early 4-piston fixed caliper disc brakes, (small bolt, 5 on 4 inch) the upper A frame is the same as the one used with the drums
DD

All '73-'76 A-body upper control arms work for the late disc swap; the control arm design depends on the year and not the brake type. I think E-body upper control arms are identical too. I do not know if the '66-'70 B-body upper control arms will work; the ball joint is the correct one but I do not know what the dimensions on these arms are. I <i>think</i> they will work correctly but am not sure.

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

Again, would I have to have the booster and master cylinder that appears to be missing, or will my master cylinder work by itself? I don't know squat about brake systems. The Volare has its front disk brake system intact. How much of it should I consider robbing? The rotors appear to be considerably grooved. How much can be safely machined off? I read other discussions about how the design of the F-body spindles might actually improve stability. Would I be better off going with the Volare brake components and forget the Swinger, even though the Swinger is the same year model A-body as my Dart Sport?

What should I hope the rear end turns out to be? Is the 8-3/4" better than the 8-1/4" in some way? What's the story on the sure grip?

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There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

go here. this is a great article on the swap.

http://www.moparaction.com/Tech/archive ... ipers.html

as for the rear, the 8 3/4 never had a large bolt pattern from the factory on the a-body cars.

-james

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So then, I should expect the rear end to most likely be the 8-1/4", especially since the Swinger originally was powered by a 318.
Then again, didn't some of the 7-1/4" come with the LBP?
If it would just quit raining every other day, I could go crawl under there and look for myself and end this mystery. Of course, that would take all the fun out of this treasure hunt.

Jerry

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

i'll guess and say yes that it would be an 8 1/4 since it is a v-8 car with discs (largs bolt pattern.) BUT, my current parts car is a v-8 dart and it has a 7 1/4 LBP rear and discs while another parts car i had years ago was a slant six with an 8 1/4 and discs. i have never seen nor heard of a small bolt 8 1/4.

-james

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The focus for my son and I doing the Dart Project is to provide him with a first car that is reliable, safe, economical, easier to maintain or repair, look cool and have a little attitude (nothing major). That's why we stayed with the slant six for now. I have spoken for the Super Six we found at the scrap yard and will get it soon. We don't plan to take it on Sundays to our local Temple-Academy Dragway (that's in Texas). However, someday he may want to upgrade the car to something more serious (at his own cost). We do have a 360 engine stashed away for a future adventure.

We are learning a lot about auto mechanics from this and other sites, and we appreciate everyone's comments. So, let me pose this question. If you were given the following choices, what would you do?

1. Look for 7-1/4" rear end with LBP.
2. Take the LBP rear end we found, if it is 8/1-4".
3. Look for 8-3/4" rear end and modify with LBP axles.

How would the Sure Grip play into this equation?

Obviously, options 2 and 3 would require some drive shaft modifications. Would it be prudent at that time to retrieve the drive shafts of those donor cars, if we go that route, or just modify ours? This all brings up another question I see discussed ocassionally. What would be a good gear ratio to run for a daily driver on the street, but still have a little attitude off the line, if challenged?

I look forward to some spirited discussion.

Jerry

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

yet another can of worms! i currently run a 3.91 sure grip 8 1/4 rear in my 70 swinger with a 318/auto it works fine. these rears are pretty cheap and plentiful (still in production after 30-something years) compared to the 8 3/4 rears plus they already have the large bolt pattern. the 8 1/4 rear came factory in the 74/up 360 and 73 340 a-bodies so it should be fine for your "future power." however, this prediction is really dependent on how much power you expect to make. i hate to guess but any more than 300 hp at the rear wheels will probably be pushing the limits of the axle. sure grip units are generally tougher than their "open" counterparts so i would recommend using one. don't bother with used stuff since these units can be had brand new for under 200 bucks. cheap, easy and reasonably durable make these rears quite attractive.
there are some downsides to consider. first the axles are retained by c-clips (ala GM) which isn't the hot setup for high power cars since a broken axle can slide out of the axle tube causing catastrophe. these clips bear much of the cornering load and can get so worn that they can fall out. these are cheap and easy enough to replace with simple hand tools. second, the axle bearings ride directly on the axle shafts, if a bearing were to go bad, the axle will most likely be ruined. let me tell you now, i hace had zero problems out of my rear since i built it 7 years ago.
obviously, the 8 3/4 is the way to go for serious power. these were used behind all the hot motors from the factory and can take a real beating. the main reason i do not have one is cost. thse axles used to go for 50 bucks but now people think they are made of gold. 250 bucks seems like the going rate for an a-body unit, but factor in another 2-300 bucks for lbp axles plus backing plates/drums/new driveshaft and you see what i mean. thse rears are probably the best design around, having none of the aforementioned cons of the 8 1/4, plus good aftermarket parts support makes them very attractive in spite of their price.
my advice? if your parts car has a 7 1/4 lbp rear just go ahead and use it. they are kinda weak, but it's a bolt-in and should live behind your hot six. they are also the lightest rears for your car, which is a plus. then you can shop around later if you make hard plans for a v-8 swap and really know which route you want to take (8 3/4 or 8 1/4.) if you wind up with an 8 1/4 that's great! get the driveshaft and away you go. it will be a little heavier, but that's ok since you won't need to swap it right away if you build a mild v-8 later on.

-james

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