It's no secret which one I prefer. (he-he-)
The Brumfield Heads will guarantee you plenty of bang for the buck! They are proven products for any performance output within the range of a flatheads's capabilities.
The B-F 5.9 alone adds anywhere from 10 to 15 MPH top speed increase to your A engine. If top speed is not your thing then climbing hills in 3rd gear are a breeze where before you had to shift to second to make the grade.
Brumfield Heads have been manufactured from as low as 5.2 to 8.5 in compression ratio with heads greater than 5.9 (known as Brumfield Super Heads) being different castings. The 5.9 has been refined several times over the years with slight changes which added peformance and the next batch will have another change that I've already tested on my dyno to increase the power even more without changing the compression ratio.
As for the B-F Super Heads, besides the different compression ratios, only a few of them are exactly alike nowadays because nearly everybody is changing their valve size, the lift plus the valve thickness is different, carburetors, cams, different deck heights, etc., etc. and the B-F Super Heads are made to accommodate them individually. As an example, Speedy Ed J. received a B-F Super Head a couple years ago that was different than any I've made. With his Brierly Cam and valve thickness, the total distance from the flat of the valve to the block was .444 thousandths of an inch!
Larry B.