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Too much compression for the iron heads and mild cam. The power will come from good flowing heads.
Installing 84cc Edelbrock RPM heads will lower compression a bit, and they flow much better than stock (unported) heads. A larger intake manifold will help too.

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Way to much compression if you make it actually have 11.4 mechanical compression ratio with any iron headsI live at around 4400 FT above seal level in central Oregon, I have had one of my iron headed(906s, with 9.25 to 1 comp ratio) ping at 14.2 to 1 AFR according to my wide ban, another aluminum head(Eddy RPM) does not ping at 10.4 to 1 comp. ratio you don't want to detune the motor to avoid pinging or detonation so buld it to make max power on the fuel you have I have another 906 iron head stock stroke motor similar to yours, it is bored +.060, not .040 and it has a set of forged Speed Pro six pak pistons set at -.020 deck hieght,9.46 to 1 comp ratio,Eddy Performer RPM intake and a Holley 959 HP carb, Comp Cams XE285HL cam and lifters, that motor makes 512 HP at 5000 RPM and 544 ft. lbs. torque at 4000 RPM on Oregon pump swill, no pinging at all. Make sure and run a colder spark plug heat range and then you can advance the timing a little(36 to38) for the altitude to start the burn sooner in the less dense air

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I live in Arizona at just under 5000' altitude. My engine build is for high performance street and I am trying to achieve a quench motor design with maximum power.
Looking for some help here BEFORE I have any machine work done on my block.
I have a 1968 440HP block that is standard bore at the moment. I have the 915 heads, the pistons (TRW 10:1 @ +.040), roller rockers, Eddy Performer 440, 870 cfm Holley Street Avenger. 4 speed with 3:54 Dana.

Here is what I am considering for my build:
Bore .040", machine to zero deck, 915 heads with 2.14/1.81 valves, 74 cc chambers, stock forged crank, forged flat top pistons, .039" felpro gaskets, leaning towards the Hughes 3237 camshaft with 232/237 duration @ .050, .576/.584 lift, 110 LSA with 1.6 roller rockers.

Premium gasoline is 91 octane here so my questions are:
What cylinder pressure should I be shooting for?
With valve reliefs CR should be 11.6 is this too much?
What modifications or changes to my plan would you suggest to achieve my goals?

Thanks in advance. I really want this to be right and altitude density is an area I don't know a lot about.

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Don't know exactly where you live in Az, but I'm in Payson @ 5000 ft above sea level. The tracks I race at range from 1300 to 3100 ft above sea level. I have actually watched the DA change as much as 3000 ft in a matter of an hour out here. I would suggest you build for around 1500 ft. - unless you don't plan on leaving your back yard . I would not go over 11:1 with iron heads. I have run that cam in a SB. You will like it for the street. You will need a minimum of 160 cranking psi with that cam and you shouldn't have a problem achieving it at 11:1. Actually 10.5 would be safer. I run 11.5:1 and I gotta run race gas ( 100 octane ). Only other changes I would make: Bore .030" if you can. It could give you more boring lee-way in the future. Keep the pistons about .005 below deck. Again, just gives you more room for a future build.