what difference between OEM brake cylinder bore 1.00 and aftemarket cyl.bore 1.032?
I agree what 1981TA's post #19.

The smaller bore master will produce more pressure, but not move the volume. If you have say a 4 piston caliper setup in the rear and a 2 piston(race caliper) in the front then the smaller bore is fine as it will not require the volume to move the pads like a full 4 piston system will.

Both will stop the car, it is common if you have too small of a bore to have to pump the pedal a time or two to get the pedal to come up. The larger bore will require a bit more effort, but the pedal will not move as much. The smaller bore will require less effort, but travel further.

I am running a tandem master for manual brakes (old school Mopar aka Strange master) with factory LS1 brakes. You will need a new pushrod, it will require some basic fabrication along with pedal drilling for more pedal leverage.

Personally I prefer the feel of manual brakes because I'm used to sensitive braking. GM has a bit of dead space at the top of the pedal travel and it pisses me off. If I hit the brake pedal I expect calipers to bite immediately. Oh and I can still brake with the motor off.

MOST with manual brakes are ditching the booster for weight as a race car. Race cars with bigger brakes need the larger bore master to compensate for larger piston volume.

All the Ls1tech vendors and a couple race shops I talked to offered the 1.032 and 1.125 cylinders in their kits. Vendors and Strange all told me to go with the 1.032 if I was using the stock brakes and 1.125 for race brakes.

I went with the Burkhart Chassis kit, I liked the way the line lock was attached to the master cylinder. I use the 1.032 bore master with stock brakes, the car stops so much better than I thought it would.

I've wondered about doin this also. Good thread op.

Did you leave the abs in place?

No, ABS is completely gone on my car.