looks like you have a 1972 or 1973 429. If the heads are D2VE, then it's a 1972. If the heads are D3VE, then it's a 1973.
The D2VE open chamber head is a single-year production head and should be discarded for performance builds. If you have the D3VE heads, then they can be made to work up to about 400-500 horsepower depending which direction you go with them.
As with the post above, what are your intentions? Street/strip car? Drag only? Desired horsepower? Pump gas friendly or is race gas only okay?
You might be surprised how quick and fast a 400-hp Fox body can be.