They will be pretty close to the same increase in power as compared to a SBC.
I had a positive deck of .002-.004 w/the Felpro HP head gasket 4.125" bore. I did run 91 octane w/no detonation. (More info if needed)
If you are going to use a large chamber head, that will be less compression than a 194 cyl head.
Don't know what cyl head you are referring to.
You could run even low octane depending on what camshaft you use.
Say the combo you are going for, zero deck, 250 flat top pistons, .030" off the head & use a cam w/duration in the 260-270 degrees @ .050 on a 106 lobe center, you will be bleeding off a lot of cyl pressure. You will most likely not get into detonation.
But if you have the same combo & use a camshaft w/ 210 degrees duration @ .050 on a 114 lobe center, you will more than likely get detonation w/premium fuel.
It is all in the combination of parts all working together & carefull selection of parts, fuel distribution, timing & other things greatly effect how an engine is going to run.
Would need to know your whole combo of parts to further determine what you could possibly get away with while running pump gas.
MBHD
