1966 Ford Galaxie change my head?

Not in my experience.
Did any of these people give you a reason?

and most of them came with 4 barrels on them anyway.

Do you have a 352, 360 or 390?

i have one and it have a stock 2 barrel its a 390 engine everybody have say the same thing! some years youre ok and some years you must change your motors head because they are not the same!
thank for posting!.......

The only reason i can think that you would need to change the heads, is because the 4bbl intake manifold wont bolt up to the heads.