Drum to disc conversion on 70 E-Body with Hotchkis TVS

what your budget?

Depends on your budget, how fast the car is going to be, and what size wheel you're willing to run.

I covered all of the available options in my B-body book. I'd suggest starting there since that is the latest information available.

It's going to be running 18 inch wheels, with a 383, and we're not looking to go crazy with 6 piston calipers, since it's not going to be a full-on race car. We've been looking at Wilwood kits, we'll have to check out the others too.

The DoctorDiff SRT kit would be a good fit with 18 inch wheels. It is a better value than any of the Wilwood kits. The Baer T4 kit might also be a good fit for you. I covered all of those in the book so that is the easiest way to see all the kits side by side.

I'm running andyf's 13" viper kit is a decent price (although you source the calipers yourself) the wilwood from what I've read are not worth it unless you get the 13" disk 6 piston caliper setup, at least for the fronts...doctor diff also carries andy's kits i believe...

I have 2 cars with Wilwood kits front and rear, so here are my thoughts on the subject.

I wanted to have matching front and rear calipers for aesthetic reasons, si I took a Wilwood rear kit to match the front. So did a friend of mine, and I ended up buying his car (no, I didn't do the same mistake twice )

If you want to convert the rear brakes, look into this first, and read around to find out if you want to retain the OEM tapered bearings or switch to Green Bearings... This has been covered on Moparts before.
In my experience, green bearings and road-racing don't mix. That rules out some of the kits on the market. Some people here might say the Green bearings are OK, but in the "Corners are best" section, I dare say they're not...

Depending on the diff you have, you may be able to fab a spacer to install between the axles, or you may not (with a Truetrac, you can).
Remove the center section and measure between the two axles for the spacer length.
Some diffs are not see-through, and you can't do this (or fab 2 spacers?)

You can also switch to longer axles .

It's much simpler to start by chosing a kit which works with tapered bearings. DrDiff has some (Cobra calipers with cable-operated E-brakes, I think)

If you install green bearings and take your car to a racetrack, the life expectancy of the bearings drops to around 20 minutes.
If you remove the inner seal from the green bearings, and don't drive too hard into corners, they'll live.

Oh, and the aluminum flanges on the Wilwood rear kit (which hold the inner drum parking brake) can bend. The parking brake is so weak it's barely noticeable.

If I had known all this before switching to discs, I would never have used a Wilwood setup on the rear.

For the front brakes, all I can say is that a 13" rotor, 6-piston caliper setup with 1.25" MC and hydroboost assist is great for both track and road use...

Did the Wilwood aluminum backing plate bend in the center by the bearing, or out by the caliper?

I usually suggest to retain stock 11x3 drums and tapered bearings for any car that is going to see more street than track miles. On our cars we replace the green bearings every 3-4 events due to excessive bearing wear and subsequent pad knock-back. there are a lot of band-aids to this system, but if you are going to reliably track and auto-cross a Mopar, look into a full floater!

Too late for you, but the DoctorDiff rear disc kit is the way to go on a Mopar. It keeps the tapered axle bearing and it actually fits and works right out of the box. Some of the "big name" kits that I've worked with don't actually fit. And then the customer service is lousy to boot. Not much more than "you bought so you figure out how to make it fit".

Just set the end play up on the tight side of the factory specs and go have fun. It is as good as it gets without spending a ton of money.

I thought a slider caliper was the ticket with rear discs and adjustables? Fixed would definitely cause problems.

Here is my Dr.Diff 14" setup. Very nice and the rotors are total overkill on a 3200lb. A body which is exactly what I want.

With the DrDiff rear disc (smaller ones of ~10.5"?.. fitting 15" rims)... does the track width change at all from factory width? My concern is pushing the wheels out further towards the fenders as I've already nicely flushed the lips. Tapered bearings are the only way to go for cornering life expectancy.

I used the Baer Iron Sport on my B Body,it appears identical to the Dr's kit , and the rotor hat is approximately the same thickness as the drum.Also the disk kit is way lighter too.

Track width is changed a small amount. The disc center is slightly thicker than the drum center. Maybe 0.100 inch per side?

Also,the factory tapered axle bearings worked perfectly with the Baer set up,neither can I detect any pad kick back on my B body.

Thanks Andy... every fraction of an inch matters for my setup.

Thanks pro451 for the info on the Baer Iron Sport setup.

Ask DoctorDiff for an exact measurement on track width change. It isn't much but I'm pretty sure that the rotor center is slightly thicker than the drum center. If I had both parts laying here I could measure it for you but I don't have the parts on hand at the moment.

I've got the Bear 13" "track" setup on the front and stock big drums on the rear. It stops very well. The front requires the later A/E body spindles. The Bear calipers have a smaller piston area than OE MOPAR so you need plenty of brake pressure. If using PB the 9" booster is marginal. A twin 8" or hydroboost is better. Getting front rear bias dialed in requires a prop valve and even better, smaller wheel cyinders on the rear + prop valve.

I also have the Baer Track on front and coupled with the 11.7 Iron Sport on the rear,my front and rear balance is dead nuts for this 3500 pound B body.I also am using a 1.03 alloy manual master set up and only a drum distribution block .