Werby, Do you have disc or drums at the front? what bore dia master did you use?
im about to convert to a dual master but will stay with front drums.
I got the big Police brakes and with the right shoes they are more than enough
I use those solid brakelines on my Model-A
. I found a German Model-B wood gas head
from WWII, 8.5-1 CR, that realy made the engine wake up. Could you Gonk that ? 
Car is factory power drums all around. Never had a problem with brake fade even in the moutains out west here.
The wagon has the big 3" front shoes but this hardtop does not.
IIRC it was a 67 Gal drum/drum master cylinder. My dad did this one & always adds the prop valve.
Ive converted other cars & if you can find a dual cylinder with the same front&rear diameter plunger you don't need a prop valve as it's really no different than using a single master.
I actually have maybe 10-20 Model A dyno tests in the Gonk database!
So yes in theory.
But what I find on the Flatheads is, it depends a whole bunch on HOW you get the higher compression.
Kinda gives valve shrouding a whole new meaning since as you raise compression, you're "shrouding" what is now a loooooong path from the valves to the chamber. So I've seen dyno tests where compression is way up but power gain is minimal. Just depends.
It sounds like you got a good head design.
Our "A" engine is stone stock original. We had the head off to get it started back in 1965 (it hadn't been run since 1955) but nothing since then. Rod caps/mains have never even been apart. Our "A" had its 90th birthday last week! I wonder if today's iron will hold up like that & still run when its 90 yrs old. I wonder if *I* will for that matter!
Gonkulator 200cid Model A
I am guessing the .050 durations at 170-170 bur really have no idea. I should degree our spare engine & find out!
Factory Spec
Torq 128 at 1100
Powr 40 at 2300 a real revver
Gonkulator at stock 4.22 CR
Torq 127 at 2000
Powr 40 at 2700
Gonkulator at 8.50 CR assuming same breathing
Torq 162 at 2000
Powr 59 at 2900
A huge difference IF breathing stays the same, but it would be a huge kick in the "mid-range" (1000-2000rpm) anyway.