Some of the "big" Wilwood calipers have small bores. The area of the pistons is what matters. I got caught on that, once, years ago. Figured big calipers, big MC. Measure the bores, do the math and it makes sense.

Went from 1 1/8 to 7/8. Went from using 2 feet to stop to going through the windshield if you want. Pedal travel was a touch long for my taste but not a deal breaker. Owner liked it so... Don't remember the car having power brakes. Worked fine without it.

Power brakes make a difference.