I had neither power brakes or power steering in a full-fendered, all-steel '30 big block A-Bone. (Photo in my gallery). It steered and stopped just fine.

No PS/PB in my '34 lowboy either. Steers fine. Brakes fine. If your MC is below the floorboards, you need residual pressure valves in both front and rear, and a proportioning valve may work if you don't have room for the dual MC that Richard suggested.