Are the heads out of the box? I would think milling them to get to a higher compression (I'm assuming you're running race gas anyway) combined with skilled bowl and chamber porting that enhances the mid lift flows would make more torque/hp would help the ET more than a cam swap on your stock heads. From what I've seen it's not too hard to pick up another 10-15 cfm particularly in the .350-.500 range, so IMO that would be the rough equivalent of adding cam lobe "fatness" (as far as cylinder filling) without impacting the seat to seat cam/converter relationship the car already seems to be working well. pulling up the mid-lifts would be closer to making your flat tappet feel more like a roller with no downside.

Love the car!! Super clean engine compartment and great running relatively mild combo! If you must go faster, I would try a solid roller and dominator.

I think that is the most cost effective way to go for a race engine. Especially if you have the right converter and are geared to keep the engine in the 6000 to 7000 rpm range all the way down the track.
Are you going to stay with the 4150 or change to a Dominator? There are Max Wedge intakes for both 4150 and 4500 carbs, but the 4500 setup will make more power. Only issue is that then you'll need to buy a good 1050 Dominator.

Most cost effective way to go would be to buy the 270 heads with the roller cam springs so you're ready for the new roller cam. You'll have to swap your existing flat tappet springs into the 270 heads for now. But then when you're ready to switch to the roller cam you'll have the parts you need.

The dual pattern 4150 is a good idea but you have to make sure it seals up all the way around. Some 4500 intakes are opened up too far for the 4150 base plate. I used to make a 1/2 inch adapter that sealed a 4150 dual pattern carb to a 4500 intake. It had 7 degree taper in the bores and anti-reversion lip on the backside. It worked really well but not very people were interested in it so I stopped making them.

That's a shame it's a really cool piece , do you have any left I'll take one!

So my thinking or wondering is, how much horsepower is left in the cylinder heads? What is the most cost effective way to get where I want to be? Perhaps I should have opened the thread with that question.
The combination is a 3700 lbs. with me in it.72 charger. 4.30 gears . 30x9 slick .5200 flash stall converter, footbrake car. The engine is a .030 over 440 with flat top pistons, total seal gapless top rings. 11.7 to 1 compression..ootb 240 heads
deep port match trick flow intake by Hughes engines. 1.6 rockers. a 1000 cfm pro systems calibrated carb. A Hughes engines flat tappet cam 254 int,260 exh @ .050 . 640 lift int 656 exh. My best et in very good weather is a10.57 @ 127mph. avg et is 10.73 @125. The engine has 110 runs on it. I'm a lot closer to 10.5 index than the 11.5 index. Can I get 40 hp with a cam change?