This subject has been mentioned in posts before...
Some 20yrs ago, my orginal 69 master cylinder died
So I replaced with a Aussie (GM) Holden HQ master...which bolted up and only needed a longer pin.
The orginal had a 1 1/4" bore
The Aussie a 1" Bore
I have the most aursome brakes, up in the 90% on the brake machine, and the best I have had in ANY car I have ever driven...

But this morning it died and filled the booster with liquid.

A ater market 69 Camaro master is avalible off the shelf in NZ nearly $100 cheaper than the HQ...
So I now have a Camaro that breaks like what a Camaro should do...and Im disapointed....theres nothing wrong, it jusat brakes better than most other cars now...and needs more effort, with less 'feel'

I has been said that a small bore need more braking, no it takes less, and that more pedel movement...but when u actually take the less volume of the 1 1/4 move the required volume of fliud and relate that to pedal distance, one is only talking mms, which in pactical terms one would never tell the difference.

The decrease in effort needed and the very slight increase in distance gives one a very nice road feel

are you saying you like the 1 1/4" better than the 1"?
Im just wondering

US Camaros use a 1 1/8" bore, and they usually work well if you have enough vacuum to run the booster. You can cheat a bit and run a smaller 1" bore master cyl to help out the low vacuum. Many Camaro owners say the stock discs have too much power assist. I've driven several Camaros with stock brakes that felt quite different. I think the main differences are in the weight of the car and the brake pad type, tire height plays a role too.
David

I prefer the 1" bore
I have stock booster, stock discs, 235x 14 x 60 allround on ss cragers

Yeah Dave I have noticed a diff between stock cars, brakes , cornering, steering...etc to
And none are as good as mine, even with the stock 1 1/4" master...
I have other vintage/ classic cars US and English too, and they are the same...
I put it down to, I have suspension, king pins, etc etc as good as new or better parts, where as the others dont have the same high stds.???

And when the other drive my cars, they too are very suprised at the diff to.

Example Bradford Vans for the last 40 odd yrs have a reputaion in the steering to sort of wander down the road, like a tractor, sort of...my whole front end, steering box etc is fully rebuilt, and alloys far superiour to thost 50 to 60 yrs ago...no wandering

I have a 1.25" bore non-power M/C on my car, but I'm a sorry SOB, b/c it ain't on the road yet!!

I gotta get it on the road before I up and die!!

pdq67

PS., 13" rotors w/ big single piston calipers on the front w/ 11.75" rotors and Cad Seville e-brake calipers on the rear!

All make up my "pdqCBB" setup..

Finally what seems to be the answer to a question I have had for months now.

I CAN run the stock M/C (manual drum) with a 4 disc setup and a 4 disc proportioning valve.

Finally the answer!