I have two 440s with iron heads the first is a 452 built in 88 with 452 heads that have been pocket ported, port matched and cut to 80 cc. With 2.14/1.81 valves. With 9.5 cr and Mopars .557 mec cam it makes 525 hp and 545 tq.
The next one has 915 heads with more bowl work and 2.18/181 valves with 68cc chambers and 12.5 cr. It is setup for e85 and makes 645 hp 620 tq with a Comp 602/590 cam, I believe having seen several compreable builds on the dynamic with TF heads I would gain around 70 hp upgrading to them on this combination.
These two 440s have a sentimental value to me so I stick with the way they were built 30 years ago, but I'm working on a new short block that will get TF 240s.
I guess my point is you can make power with iron heads but it takes money, time if your the one doing the work and you better know what you're doing and more cam as in more duration you need to hold the valve open longer to fill the cylinder.
You also need to play with advancing the cam because you don't want peak power to happen at a point where the heads have stalled, the second 440 peaks hp at 6300 rpm and the heads stall around 6700 rpm.
Aluminum heads are easy power!
