Hi.
I have a Mercury Montclair from 1956 with a 312. The engine is out from the car for renovation of the heads and general overhaul of the engine.
I will keep it stock, but perhaps upgrade the camshaft one step from stock if possible. 
What i have is:
Stock 312 from 1956  225HP
Engineblock: Stock ECZ 6015C
Heads:Stock ECZ- C comp.9,0 :1
Intake manifold : ECZ 9425-B singel 4 barrel.
Exhaust manifold: Stock
Carburattor  : Edelbrock 1404 cfm 500
Rockerarms : ECG 6564  ratio 1.54:1
Distributor : from  y-block 1961 with Ignitor
Transmission : Merc-O-Matic 3-speed
Rear axle: stock with gear ratio 3:15

If i choose a new camshaft with stock spec. which brand has best quality (US made) and type of ? same for the lifters.
If i want little more out of the engine can i go for Isky 3000444 (E4 ) with the spec. above? or is there any camshaft in between stock camshaft and E4 with good quality?
I prefer a low and mid range camshaft , i only use the car for street and crusing, and it is importante with good idle.