[Hammertime]

I’m looking for my options with a stock master cylinder I purchased for a 73 Trans Am. I was looking at 12 inch brake upgrade kits but I was wondering if I have to replace the master cylinder. Looking for recommendations for street applications no track or drag racing. Thank you in advance.

[JLMounce]

That depends more on the calipers you are running and if you are going with manual brakes, vacuum assisted or hydroboost.

Your 73 trans am should have disc brakes up front already, possibly in the rear depending on options. If this is a street application only, is there a reason you're looking at upgrades? The 11" vented rotors with the GM D52 caliper has enough clamping force to get the job done on these cars. Where they fail is in repeatability. For a street application, that's rarely a concern.

If you want better stopping distances, you want to look at better tires and possibly a brake pad upgrade.

[Hammertime]

I had read with more horsepower (425) that you should upgrade your brakes. I have disc front and drum rears. I am either going to run 17x9 honeycombs all the way around or possibly a 17x10 billet on the rear and 17x9.5 fronts. Is there a particular tire that you recommend? As always thanks.

[JLMounce]

Having good brakes when upgrading horsepower is smart, but you don't necessarily need big brakes. What you need is a brake combination that has enough clamping force to lock up the wheels. One this is achieved, adding traction is the only real way to reduce stopping distances.

I run the Nitto NT555 G2 and have been pretty happy with it. It's decently grippy, quiet and has a smooth ride for an ultra high performance summer tire. It also has a fairly wide array of sizes that are complimentary to our cars.

I think you could definitely do a rear disc conversion and that will help some with repeatability. I would do a standard rear disc conversion that will use 11" vented rotors and metric calipers. You can use your factory master cylinder with this combination. I would upgrade the pads to something like a Hawk HP, or my personal favorite, the Carbotech 1521. Matched with a performance tire, you'll have a braking system that is well suited for a street only car.

Of course if you're wanting to go to 17" or 18" wheels and just want to fill them up with a big brake system, that sometimes can be reason to go that direction. Depending on the calipers used, you may need a different master though.

[Hammertime]

Originally Posted by JLMounce

Having good brakes when upgrading horsepower is smart, but you don't necessarily need big brakes. What you need is a brake combination that has enough clamping force to lock up the wheels. One this is achieved, adding traction is the only real way to reduce stopping distances.

I run the Nitto NT555 G2 and have been pretty happy with it. It's decently grippy, quiet and has a smooth ride for an ultra high performance summer tire. It also has a fairly wide array of sizes that are complimentary to our cars.

I think you could definitely do a rear disc conversion and that will help some with repeatability. I would do a standard rear disc conversion that will use 11" vented rotors and metric calipers. You can use your factory master cylinder with this combination. I would upgrade the pads to something like a Hawk HP, or my personal favorite, the Carbotech 1521. Matched with a performance tire, you'll have a braking system that is well suited for a street only

Of course if you're wanting to go to 17" or 18" wheels and just want to fill them up with a big brake system, that sometimes can be reason to go that direction. Depending on the calipers used, you may need a different master though.

Thank you for the advice. I’ll do what you have suggested and I appreciate the education.

[jerry455]

I have a 1976 Firebird with the 12" rotors on the front and 11" drums on the back. The stock rears were 9 1/2". I had the "kit" left over when I got rid of my 1977 Can Am. I used B body front spindles and 1LE rotors from a late 80's Camaro. I used 11" rear drum set up from a 1973-1977 Lemans for the rear, and I am using the stock 1976 Firebird front calipers and master cylinder. I can lock them up if I stand on the brakes. I have 255 60 15 BFG's and 8" snowflakes on the car.

[Goatracer1]

Just having more HP doesn't require bigger brakes. It would depend on how aggressively you use that HP. Just driving the car normally wouldn't require any improvement.

[VCho455]

More food for thought. I've been happy with the Firestone Indy 500's I've been running on my S10. Similar weight and horsepower and on 17 rims.

You may also be interested in using a 2nd gen S10 Blazer rear disc brakes set up. See link.

https://nastyz28.com/threads/s10-bla...ersion.109454/

[78w72]

As mentioned more HP doesnt require bigger/better brakes for street use, #1 you still have to drive reasonably close to the speed limits and #2 any street tire or even drag radials will break free when you stomp on it with higher HP that the car wont ever or wont usually be going so fast in a short distance that you need bigger brakes.

Example, I have a 72 firebird with a stroked Pontiac at 500+ hp that runs low 11's at the drag strip going 123mph, it still has the stock rear drums with upgraded front Hawk HPS pads & basic slotted rotors with original calipers... that car stops better at 120+mph than my 81 TA with 4 wheel disc did at 95mph.

Your 425 hp on the street doesnt need nor can really take advantage of bigger brakes, unless you want the look with bigger wheels then look into a rear disc upgrade that uses stock master then clean up and paint the front calipers & rotors to look better, with better front pads should be more than enough for a pure street car.

[jerry455]

If you are doing a lot of repeated braking, then discs can help. I put on the bigger rear drums instead of the cost of the disc brake set up that I didn't need. My brake system is basically what the big car uses. It still uses the stock master, but I put the police option semi metallic brake pads on.

[Hammertime]

Originally Posted by jerry455

If you are doing a lot of repeated braking, then discs can help. I put on the bigger rear drums instead of the cost of the disc brake set up that I didn't need. My brake system is basically what the big car uses. It still uses the stock master, but I put the police option semi metallic brake pads on.

What size rotors do you have on the front? What size drums are you using for the rear?