There are some pretty extreme variables to answer your questions.

As for the octane requirement for example,  camshaft selection alone will determine at what point you will be out of the pump gas category. 10.5:1 is typically the max. Heard of more and less.

You really need to look at the dynamic C/R, not just the static.

If you are working with a machine that does high performance engines, they should be able to set you up in the right direction.

Another thing to consider would be if your current heads will have the ability to take advantage of more compression.

I am on a job site right now having a much needed cup of coffee, but will be able to pay with some numbers later and give a rough idea of where your at now.

I'm thinking off the top of my head your in the 8.5:1 ballpark, but don't hold me to it.

Corrected from 9.5 to 8.5:1

Pretty typical actually.

Sent from my SCH-I545 using SoCal Jet Boats mobile app

I'll give you the run down of what I'm running, it's .030 over 454 4 bolt block, closed chambered 291 rectangle port 107 cc heads, the pistons are Keith black flat tops with single intake valve reliefs, standard felpro head gaskets, the cam is advertised duration of 284/284 and lift at .544/.544, the intake is a port matched team G, and running a Holley 800 DP and I think the jets are #85 in the front and #87 in the back.

That's kind of what I was thinking I was going to have to do, it's in a 19 ft hornet with a stock Berkeley E pump, ride plate and a manual place diverter.

A "standard", as in most common, Fel Pro BBC gaskets are 9.700cc.  Those KB pistons have a valve relief volume of 3.0cc and a 1.645" compression height.

If your block has not been decked, that would put your compression ratio at 8.58:1.

If your block was zero-decked, your compression ratio would be 8.88:1.

Really need the Lobe Separation Angle (LSA), AKA Lobe Centerline Angle (LCA) (not to be confused with intake lobe centerline), or intake/exhaust duration overlap in order to calculate the dynamic compression ratio.  The intake valve opening and closing points would be ideal.  Also assuming by lift and duration that this is a flat hydraulic lifter cam.

Throwing out a guess, assuming a 112 LSA installed "straight up" and a zero-decked block, your dynamic compression ratio is about 7.11:1.  Advancing the cam 4-degrees will bump it up to 7.31:1.

If you stepped up to a 12cc dome volume piston, your dynamic compression ratio would be a safe 7.98:1 and advancing the cam 4-degrees will bump it to a still safe 8.22:1 with a 10:1 static compression ratio.

If you wanted to push the limits, careful attention to detail of the piston domes, combustion chamber, quench distance, and mixture motion could allow you to squeeze a bit more.

IMHO, your compression ratio with the flat tops is way too low for 93.  At the performance level you are at, I would zero-deck the block and run the 12cc dome volume pistons with a good tune and enjoy.

Cheers,

Joe