Hard brake pedal?

The same thing happened to me when I replaced the front drum brakes on my 1970 Duster with Wilwood disc brakes. Turns out disc brakes require a lot more applied pressure than drum brakes. With power brakes the required pressure increase from drums to discs is not noticed but it sure is noticable with manual brakes. I suggest that you also read my very recent post in this forum about RedBore brakes by Just Suspension, it may keep you from making the same mistake that I did.