They will physically work, but my question is why, unless they have a bunch of work done to them. They will need hardened valve seats if you plan to run any unleaded fuel through them. Like I said, unless they have been heavily ported, stick with the stockers.
I have 69 windsor heads on my 306 and it hauls ass. I got the heads real cheap from a friend and he has a buddy who runs a machine shop. So, I got a good deal on everything. Plus its nice having a setup that most people don't have. Using old school Ford power If you have the money though, aluminum heads like AFR and TF twisted wedge heads are real nice.
my heads were ported, milled .080", we kept the factory size valves (short on money at the time) but the machine shop guy did a 5 angle valve job. The valve springs were upgraded though, buddy had some in his garage I could have. machine shop guy said the heads should flow around 230cfm on the intake side. All together w/ guidplates, rockers studs, and hardened pushrods, hardened valve seats it cost me like $650-700. with traction and suspension I think I can get high 12's-13.3...but I have a GT convertible