The 1972 model year of the 429 is the one and only year with the open chamber heads. These heads proved to be so inadequate in their design that Ford ditched them after a single year. IF you have those heads, then you are better off swapping them out for another set of heads.

The casting number of the heads is located on the outside of the head, along the valve cover mounting rail and between the 3rd and 4th exhaust port. The crapppy 1972 head casting number is: D2VE-AA. If you have these heads, it would be best to consider acquiring another set of heads for a head swap over the weekend. The nice thing about this is you can keep your car running while you get the other heads ready.

The heads best suited for replacing the D2VE's on a 1972 engine would be casting numbers C8VE-A, C9VE-A or D0VE-A. These heads will increase your compression ratio from about 7.8:1 to about 9:1 and give your car more pep. Changing to these heads will require also changine to a different rocker arm arrangement that came on all passenger car heads prior to your smogger D2VE-AA heads.

The only other head out there for a carburetted 429/460 is the D3VE-A2A head. This is the head that replaced your D2VE-AA head. Unfortunately, while this head can indeed be made into a performance piece, it will not offer a significant power increase in your situation with your 429.

Finally, the 1972-up carburetted 429/460's have an emmissions camshaft profile and a retarded timing chain to go with it. So there is still work to be done after the head swap.

In summary, the head swap with some mild porting on the heads will make a very big difference in your street-driven T-Bird. Then, when you choose to do a complete rebuild down the road sometime, you can address the motor as a whole and tackle of the other stuff in the shortblock.

Paul

p.s. I have all the parts to make the cylinder head changeover to your engine: heads, rockers, pushrods, etc. Can do fresh vavel job and some mild porting too. Email me if interested.