Valiant to Duster disc brake/rear brake swap

[Fawkes]

Good morning everyone, im sure this has been discussed 1,000 times but using the search feature I was still having a hard time getting a definitive answer, or maybe just getting it through my thick skull.

I have a '74 Gold Duster with the slant six and SBP manual drums all around. 10" front - 9" rear.

I am acquiring a '73/'74 Valiant 4-door BBP, power disc, 318, unsure on which diff yet (don't have it home)

I would like to convert the Duster to Big bolt pattern and also Disc in the front utilizing parts from the Valiant. From my understanding they are mostly interchangeable brake/suspension wise. My questions are:

1. If I pull the entire disc brake spindles from the valiant, will they be a direct swap to the Duster? Or will I have to change control arms, tie rods, ball joints, etc.

2. The Duster, although drum all around, has a manual disc master cylinder on it. I would like to keep the manual brakes for right now, because id rather not mess with rebuilding or replacing the crusty looking booster. Can I swap to the disc in front, but keep my non-power disc master set up? Will I need a proportioning valve, either aftermarket adjustable or do I need to use the original metering block from the valiant?

3. I don't have the valiant home yet, but will a 7 1/4 BBP (assuming) rear end from the valiant be a direct swap to the Duster?

Down the line I would like to pull the 318 and get the V8 K-member out from under the valiant, and swap the rear end as well. But for right now my plan is to take it one step at a time, and focus on the front disc conversion. I appreciate all of the information you guys are willing to give! In the meantime I am going to do some more reading...

 

[vitamindart]

you will need the upper control arms and lower ball joints along with the spindles. the prop valve for disc or adjustable would be a good idea as well.
valiant, dart, duster, demon all use the same rear axles. rear axle would be an easy swap, just a set of u bolts & shocks holding it in.

 

[Fawkes]

you will need the upper control arms and lower ball joints along with the spindles. the prop valve for disc or adjustable would be a good idea as well.
valiant, dart, duster, demon all use the same rear axles. rear axle would be an easy swap, just a set of u bolts & shocks holding it in.

Thank you for the information. So I should be able to use the lower control arms that are on the duster already, but I will need to get Duster disc lower ball joints? Or should I order a set of 73/74 Valiant lower ball joints?

 

[vitamindart]

lowers are all the same ( unless they have sway bar tabs ). just leave the ball joint bolted to the spindle when you transfer them.

 

[YY1]

I'd be tempted to put the whole K frame, 318 and all into the Duster.

 

[valiantpatrol]

If you replace your lower ball joints you need to order the ones for the disk brake application or use the ones off of your disk brake donor. I can't confirm this but someone told me recently that the '73-'76 10" drum brake lower ball joints are the same as the disk brake ones in those years. So measure before just changing parts out have a part guy look them up. You can run manual disk brakes but you either need to buy a manual disk brake master or remove the residual pressure check valve from the port going to the front brakes from your drum brake master, or use the donor car master. Modifying your drum master nor using your power disk brake master is ideal as it will make brakes more difficult to apply. The manual disk master cylinders have a larger piston in them to make brake application easier when not power assisted. You should use the proportioning valve from the donor car also. Drum brake cars just have distribution blocks and are not "proportioned". Rear end will bolt right in but there are two different rears with BBP, a 7 1/4 like the one in your 6 cyl Duster and an 8 1/4 heavier duty one which will require shortening the driveshaft. Your donor car could have either so check to avoid surprises.

 

[hwd2]

If the Valiant hasn't been stripped yet, try the jiggle test for ball-joints and tie rod integrity. If the donor parts good then save some $ by using them. Same with the upper control arm bushes. Use whichever UCA that has the better parts but be aware that the adjusting bolts/cams may not want to come apart (if rusted into the inside core of whichever bushing). Had this happen to my '70 so was a huge project removing the uppers. Most likely yours will come apart. Check the sizes of upper ball-joints on both vehicles. If your Duster has smaller version, and still 'tight', it can be used on larger disc-brake spindle - but a spacer will be needed.

 

[AndyF]

Best situation would be to park the donor Valiant next to your shop and start tearing all the parts off it while you are working on your Duster. If the Valiant parts are in good shape you'll want to transfer the entire front suspension including the brakes and K frame over to your Duster. The late model design is better than the early design so if you can avoid buying parts twice that would be good. But as always, you'll just have to do what you have to do.

 

[RedFish]

I dont know if anyone makes adapter mounts to put a slant 6 on a V8 K. I would leave the Duster as is and drive it while I pull the 318 and rebuild it, the trans, and the suspension as if the Valiant was going to be my next driver. Once its all done, running and driving like a new one, all of it can be moved to the Duster in a weekend. After a few weeks of enjoying the Duster you could poke all you pulled under the Valiant so its at least a roller again.
It will be easier to forfeit the power steering. Keep manual steering gear and that column. Use the Valiants proportion valve, fluid lines and all. Buy a manual brake master cylinder for a 73 Valiant with front discs. Push rod from Duster might transfer too. I personally would want the power steering and power brakes but its not my Duster.