454 top end question

[70nova]

I have been doing a lot of research and thought I would run this combination past some of you.

Chevy 454
bore: 4.310 Stroke: 4.00
cyl vol: 956.32cc
Total vol 466.9 ci

Heads are stock iron closed chamber 215's with roller rockers and some upgraded springs nothing fancy. intake 2.065 exh 1.720

CR: 10:1
combustion space: 106.26cc

cam: hyd flat tappet
int lift @ valve: .502 in
exh lift @ valve: .527 in
lobe center: 112
valve overlap: -5
int duration: 214
exh duration: 224

750 holley vac. secondaries
edelbrock air gap
long tube, ceramic coated hookers
and a big huge aluminum rad with 2 electric fans
built th400
4:10
3000 stall
12 bolt

right now the engine dyno's at a little over 510 ft lb @ 3500 rpm.

I'm looking to bump this to about 550 hp and even more torque.
What i have come to believe is that I can do this with a set of 781's or 049's and some serious machine work; and a cam.

What is nice about this engine is the big torque numbers down low - but its time to move up.

what I'm worried about is changing the heads out and losing my compression or throwing something else out of whack.

Anyone have a specific cam head combo or head porting suggestions?
Is this even doable without re-building the bottom end.
I am just trying to avoid throwing some variable in the system and losing power.

sorry for the long read
and thanks in advance

[NEokcTERROR]

If you throw money at the heads you have they will work well and retain your compression. The farthest thing out of whack I can see is the tiny camshaft mixed with a 3,000 converter and the 4.10 gear. It is just screaming for some air to go with those other parts. How about something in the 240deg @.050 range with 2.19 / 1.88 valves some porting, chamber polishing and unshrouding work?