Thoughts on 4 wheel disc brake kits

Howdy, with the plan of having a very hopped up 351c for the street, I estimate 500ish at the crank at least, I am considering brake upgrade options. Currently it is all stock with power front disc and rear drums in rough shape. Suspension is most likely a small stock upgrade replacement parts across the board, came with the car dissembled everything is from the 2000s brand new never used, thicker sway bar, new leafs, shocks, etc. Essentially it will not handle the best compared to a coil over conversion or such so take that into account with brakes. It also has a 4 speed and I am a fan of down shifting and coasting to slow down slowly, the brakes are mostly only used at slow speeds or in emergencies. My question is should I consider going with a 4 wheel disc brake kit, if so what are some quality kits. Or should I keep rear drum and front disc and just spend the money on quality replacement parts like new lines, rotors, master, etc, etc. I know brakes are the worst area to skimp on but I have heard conversions tend to not be worth it so I am interested to hear yall's opinions. This isn't for autocross applications or anything, purely for emergency and being able to handle the power in worst case scenarios. Thanks.

4-wheel disc are nice but not really needed for most of us. The stock disc/drum combination, refreshed with quality parts and pads/linings work well. Unless, of course, you're spending a lot of speed time on the road courses.

There's only a couple reasons I'd say go with 4 discs. Looking cool and ease of maintenance would be the main selling points. Functionally, drums on the back are fine.

I run oversize 4 wheel disc and like them. BUT I must agree with Sheriff and giantpune, most "street/strip" applications really not needed.

Factory discs and drums with performance friction materials, not parts store stuff that fades after the first stop. I'm running Hawk Street compound fronts and a set of NOS HD semi-metallic shoes in the rear drums. Porterfield makes a street compound shoe - R4S in the 152 shoe size for $100.

Hawk Performance HB646F.526 HPS Disc Brake Pad

https://porterfield-brakes.com/product/shoe152/

Unless you are tracking the Mustang competitively you really do not need rear disc brakes - assuming you are using high quality, performance related friction pads and linings on a stock power front wheel disc system. But, if you absolutely want to get a 4 wheel disc kit I urge you to get a complete kit, to include the new rear calipers and rotors, and the correct Master Cylinder. The oem Master Cylinder's rear brake fluid outlet port has a Residual Pressure Check Valve (RPSV) located under that port's brass seat. You do not need, and definitely do not want, a RPCV on any of the hydraulic system when the brake system is connected to a caliper clamping down on a disc. Also, in many cases the bore diameter for a Master Cylinder for a disc system is not the same as for a drum based system. If you get a complete kit from a reputable vendor (Wilwood would be my choice) you will do fine.

The attached document is more oriented to replacing front drum brakes with a front disc system. But, there is a lot of similarity when looking at doing a rear disc setup.

Personally, if you are already using Power Front Disc Brakes, I would just install some high performance friction pads, make sure the rotors are not warped or too thin, install high performance brake linings on the rear while making sure the brums are not out of round, bell-mouthed, and have plenty of metal in the friction area (not cut to an too far oversized diameter, and find something else that will provide you more bang for the buck. Frankly, unless you are truly racing the Mustang competitively you would likely never notice the difference in performance, assuming your brake system and friction pads/linings are in good condition.

Thanks for all the help guys, seems I will spend the money on new quality parts. Any suggestions on either brake line kits or good performance lines? Gonna need a whole new line system. Not opposed to doing extra labor for custom lines if need be. Thanks.

Bought the stainless kit of lines a few tears back. Great quality, bought it because rust is common in the wet Holland and I couldn’t make them for the price. I saw now that these classic tube kits has become much more expensive, so having stainless is a choice and is no longer cheaper than making them yourself. Any other metal will do and perform just as good.

Fabrice said:

Bought the stainless kit of lines a few tears back. Great quality, bought it because rust is common in the wet Holland and I couldn’t make them for the price. I saw now that these classic tube kits has become much more expensive, so having stainless is a choice and is no longer cheaper than making them yourself. Any other metal will do and perform just as good.

Click to expand...

I was gonna suggest classic tube. They offer the stainless or the original material. A full set is $145. Not sure what the deal is, but CJPony shows the stainless as being cheaper than the basic steel ones. In most cases, the stainless would be more. I think maybe a pricing error on the website.
Classic tube also sells direct to customers if you want to skip the middle man. You will get them faster, but probably not as cheap. They are easy to get ahold of on the phone to place an order.
https://www.cjponyparts.com/classic-tube-brake-line-kit-complete-power-disc-8-1972-1973/p/MU1041O-V/

But I'm not clear if OP is looking for 4 wheel disc brakes or what. The classic tube ones are for the various stock configurations.

giantpune said:

I was gonna suggest classic tube. They offer the stainless or the original material. A full set is $145. Not sure what the deal is, but CJPony shows the stainless as being cheaper than the basic steel ones. In most cases, the stainless would be more. I think maybe a pricing error on the website.
Classic tube also sells direct to customers if you want to skip the middle man. You will get them faster, but probably not as cheap. They are easy to get ahold of on the phone to place an order.
https://www.cjponyparts.com/classic-tube-brake-line-kit-complete-power-disc-8-1972-1973/p/MU1041O-V/

But I'm not clear if OP is looking for 4 wheel disc brakes or what. The classic tube ones are for the various stock configurations.

Click to expand...

Looking for standard power front disc and rear drums now, made my decision to skip the 4 wheel disc brakes and keep the current setup based on the responses. Just was a quick side question for tubing. Thanks I’ll look into them too.

I used the Classic Tube plain galvanized steel line kit when I did my 71. I bought the front set for discs, re-used the front to rear, and made some lines for the 8" rear axle I was using at the time. When I put the 9" in, I bought the kit for the rear axle and replaced the front to rear with one I bent myself. I couldn't justify a $70 cost for a line I could make for under $10. I cleaned the lines with lacquer thinner and sprayed them with rattle can clear. Twenty years later they still look great.

Be aware that the master cylinder bore and line nut sizes changed in late '72 model year. If you see a kit offered as "71-73", you're likely to get the wrong parts.

NPD offers separate kits
https://www.npdlink.com/1965-1973-mustang/brake-wheel/prebent-steel-brake-lines?year=1971

1971 kit from CJs Pony
https://www.cjponyparts.com/classic-tube-brake-line-kit-complete-power-disc-1971-7-1972/p/MU1049O-V/

The rest of my brake parts came from Rock Auto.

Another detail. I dunno if still available but bought ‘performance’ rotors from rockauto. Ment as replacement for fhe originals. They have holes/vented and while the new one bought for my 71 are rusting in the garage where I did not paint them, these are not only good looking, they actually do not rust while my 73 is outside. Covered yes but in the wet air. Wish I had bought these vs the ones I bought for my 71. Affordable too.