I have ran a lot of iron heads stock and with Major work on them on cars we have raced. With all the work you have done on your Iron heads you will not get $1000 worth of HP or ET with the EDDY's. I have Ran both.

440 source heads, (I have not ran). I have used the Mopar Heads but I think you would want a bigger cam with them. They have raised ports etc
and are more expensive.
If you did not have all the work done to your heads, yes it would be a good investment. You probably have $600 or more in your heads.
Positives:
Like others have said you will loose weight in your car and it should run cooler.