I have a 74 cuda with factory power discs. I just bought the wilwood brake kit with the 12” rotor. Wilwood quoted me which of theirs to use but it’s $350. Is there any other options with a smaller bore? I plan to run just manual brakes.

What size bore did they say to buy for your deal?
My Cuda has dual Wilwood master cylinders with a balance bar mounted under the floor, dual Wilwood calipers on the rear with the same size single calipers on the front.
I replace both M.C. and all the pads two years ago to be safe, I don't remember their M.C. being that expensive back then
I can look at the old ones in the morning to see if there is a part number on them to see what size bore they are if you want to find out which size mine are.
I think my rotors are either 11 or 12 inch diameter max, not the bigger road racing ones.

Dr. Diff has some options that are priced well and work good. I run wilwood brakes all the way around with one of his master cylinder kits. Way less than $350

I have Wilwood disc brakes on all four corners of my 64 dodge, and I used a master cylinder from an 1989 Ramcharger to my memory. It looks exactly like the masters Wilwood offers. I just browsed in the parts book at the local parts store for the bore size I wanted.

DoctorDiff hooked me up with a 15/16 bore master and all I need for around $200. Thanks guys.

On my cuda I went thru mancini. Picked up a 1.032 bore. I'm using wildwood 12.19 fronts and 11" rears(if I remember the rear size, ive had them since 1988). The fronts are a new addition. Car hasn't been to the track yet as the engine isn't completed.

I have wilwood 11" disc on my front and 10" stock rear drums with manual brakes and ordered the 15/16" from dr diff as he recommended for me. Pedal has a good feel

https://www.dragstuff.com/techarticles/RacingMasterCylPN.html 24 mm is 15/16 i have on both my cars works great and costs about $28

I ordered the same fronts but will have a 10” drum on the rear.
Cab, I lost the part number for the master they recommended but it was billet aluminum and 15/16 bore, with a proportioning valve seperate and a 10% reducer since I don’t have rear disc yet. But the master alone was $345

the one thing to remember about using the front drive masters, they were all power brake masters, therefore, they don't have a means to retain a manual brake pushrod.
you will have to machine the rear piston for the rubber retainer, or fab a positive stop to make sure the pedal pushrod won't fall out, causing a bad day for sure.........

Check rock auto, or local parts store, these are only $40 and have lifetime warranty