You don't need to get custom steering and pedals, just find a nice donar car or cars.
I have a GM 4.3L V6 in my M38 (3a) the steering is a Saginaw set up, power steering pump, clutch, gas and brake pedals and linkage from a chev S-10, steering rack from a CJ-7. They all work nice with the motor.
Your going to want to beef up those axles and brakes, 200hp will start bending stock axles and the stock brakes won't be much use either.
And if you want to keep the low hood line of a 3a, a 1 1/4" body lift will give you clearance to mount your motor without having to go to a 3b body and hood.