What is better for racing? A high profile Z head or low profile head marked with a 24 on the rear of it. I have both and was wondering the difference in the two.
high profile = more auxilliary coolant.
I find for racing it's best to have the valves in the head Aka rajo or fronty or dream big, gallvian
The low type alu high compression head available from the vendors has this type of combustion chamber:
http://www.modeltford.com/i/c/945l.jpg
Much the same as a std Ford head, just higher compression.
The Z (and Prus) heads are only available in the high style, but besides the higher compression they have Ricardo style squish areas over the pistons, something recognised by engine designers since the 20's as giving more efficient and powerful combustion in a flathead engine:
So has anybody done any kind of comparison driving between the different heads? It could make an interesting experiment.
The Tulsa Model T Ford club did a lot of that years ago: http://mtfctulsa.com/Tech/heads.htm
http://mtfctulsa.com/Tech/head_dyno_testing.htm
" A 5.7:1 compression ratio would theoretically produce a 25 percent power increase, and yet the Z head and Riley head produced a 42 percent power increase. The greater than theoretical power from these heads is evidently due to their improved combustion chamber design."