OK, let me play devils advocate here. (For the record my panel has firewall mounted boosted brake and clutch MCs and front disk rear drum brakes some of which I inherited from the PO.
If you are a purist, keep the MC under the floor, When I got my truck it had a combo of underfloor brake MC, hanging clutch pedal and firewall mounted clutch MC, so I got to experience both. I definitely didn't like the feel of the thru the floor pedal operating arc compared to the hanging pedal, didn't like the breeze thru the hole in the floor blowing up my pants leg, or the thought of cutting a hole in a brand new carpet. Didn't like kicking the pedal arm getting in and out (I have big feet). Didn't like the manual (but new) MC with the front disks. Worked fine but required much more pressure than I was used to using. On the drive home with the newly purchased truck, my wife said the manual brakes had to go if she was going to be driving the truck, especially with the car hauler enclosed trailer on the back, They made her "nervous" (she was a 2 time national champ autocrosser so this said a lot). The issues with checking and filling the fluid level with a booster (and still another hole in the carpet). sealed the deal, the underfloor setup had to go. I think the simple in form and small in size cast aluminum GM MC with translucent plastic rez and SS dual diaphragm booster is not unattractive when balanced with the SS MDD AC/heater hose trim on the other side. Who needs to look under the hood besides me? Everything under the hood is mechanical looking anyhow.
There is a lot of misinformation about the efficiency and stopping power of disk vs drum brakes. Drum brakes are designed to be self energizing, they tighten and increase the braking force themselves by design. Disk brakes are not self energizing to increase braking you have to push harder on the pedal. That's why most disk brake equipped vehicles have power assist. The stock drum brakes are more than capable of stopping the truck, engine size has does not enter the equation unless you can't control yourself from treating every stoplight like a drag racing Xmas tree from one block to the next. The two times disks have a distinct advantage is in heat dissipation, they don't heat fade as quickly since they are out in the airstream and the heat is produced in a much smaller area (but they do heat fade, ask any circle track or road racer.) and in stopping ability when excessively wet (immediately after running thru deep water. It takes drums longer to dissipate the water. When there wasn't anything but drum brakes a good driver learned to lightly left foot brake to drag the brakes or test/dry the brakes immediately after running thru deep water. Manufacturers changed to disk brakes because they were cheaper to manufacture and install and had a better appearance and allowed more clearance with the increasingly popular cast aluminum wheels, strut suspensions and FWD. Also drums developed a bad reputation when the government outlawed asbestos in the linings heat fading at relatively lower temperatures, until better lining materials were developed. Stopping power of drums is directly related to the quality/type lining material. Drums are still used in heavy applications such as on large trucks and even trains.

 

The rest of my cars are drum and work great (40's to 60's). I wouldn't change to disc if I was starting with a stocker. On my panel the disc was already there, I just cleaned everything up a bit. Personally I don't like the look of a master or booster on the firewall and ALL my vehicles are pre '65 so I'm used to the manual disc/drum feel.

 

Disc brakes are not cheaper to manufacture than drums. There are more parts required in a disc assembly than drums. If they were cheaper than every single vehicle manufactured today would have 4 wheel disc but a good portion of vehicles still come with drums (even when equipped with alloy wheels). Also since the introduction of ABS nearly all drum assemblies are dual anchor and not self energizing as they don't release fast enough for ABS to work properly.

Drums are being phased out in heavy applications. Semi's are being equipped with air discs. Europe is ahead of the USA by at least a decade in adoption. Even regular trailers are now being equipped with disc brakes.

Yes drums work fine if maintained properly but that is the key word. The self adjuster is the Achilles heel of a drum brake assembly. They never function 100%. The typical life of the adjuster is its first set of shoes, after that their function diminishes as the teeth get worn. The problem is you don't how worn one is until you compare it to a new one and most of the time you wonder how the old one even worked.

Most of the problematic brake problems that come into the shop are drum equipped vehicles. The drum brakes can look in perfect condition but cause nasty vibrations and noises.

Disc brakes are less maintenance (most vehicles allow a visual inspection through the wheel that could be performed when you check tire pressure), easier to assemble (GM's abhorrent drum horse shoe retainer is an example) and troubleshoot problems.

 

Thanks for the info. It helped. Court.

 

Thanks TLB.

 

I just mounted my master cylinder on the firewall and it is a bit obtrusive. They manufacture smaller boosters but part of this hobby is scoring cheap parts and making your own brackets and soforth. I personally prefer the brake pedal from under the dash rather than from the floor board but as long as the brakes are functional and the mc doesn't interfere with anything, I'm good with it.

Wally

 

I saw this setup several years ago at a Goodguys event. Master cylinder still on the firewall but if you look, he sunk the booster into the firewall. Still on the firewall, but a bit cleaner than seeing the booster.