I just can speak from personal track experience. C.I.,is 254
When I had the large chamber head,but milled a bit I had approx 10:1 compression & ran 14.3-14.5 in the 1/4 mile.
I then installed a 194 small chamber head w/smaller valves than the larger chambered head 1.85" as compared to 1.94" valves.
With this head my compression went to 12:1 Also had 220-225 PSi of cranking pressure,,which is pretty high.
With no other changes other than the cylinder head swap I ran 13.8-13.9 in the 1/4 mile. I would not say the HP really jumped up,,mainly the torque.
You could really feel the torque output increase throughout the entire RPM band. It just ran so much crisper everywhere!!
I never dynoed the car with this engine ,but both combos where equily tunned.
The cyl heads did not have lump ports,but had mild porting on both heads. BTW,,if you go too big on the porting,,,mostly on the entry way of the intake port you lose too much velosity & therefore loose a lot of torque.
The main thing you normally get form increased compression is more torque,,,not so much in HP if cylinder heads flow numbers being the same.
My two cents & personal expierience ,take it for what it's worth,,but @ least it was track tested.
BTW,,this was my daily driver w/12:1 compression,that I ran 92 octane.
MBHD
