S&S Super Sport & S&S "SA"
Heads and Port flow
Piston crown and combustion chamber fed and
exhausted by the cylinder head ports...
With the EVOs and Twin Cams it was usually
better to go to S&S higher flowing Super Sport heads or SA
versions with raised ports and bigger valves.
Airflow is king and the combination is the key.
There is no point in wasting your money on a hyper-expensive
set of billet heads that don't flow worth a shit or that will
cause you starting woes when you add a set of high compression
pistons.
1985 stock EVO heads were basically designed for
appropriate Mach Indexes with
about 58 to 65 horsepower worth of air at 5200 rpm...and had
ports that were a bit large to start with....Only added
compression kicked up the hp. Harley flocked in the tooling
before Jerry Branch finished his development and Branch ended
up welding over 50,000 cylinder heads to change the combustion
chamber.
Getting the right combination of cylinder heads,
cams and exhausts, not to mention pistons has always been a
trial by ordeal. You spend an endless amount of time and money
modifying your stock cylinder heads only to find out that you
have to weld up the ports or the grinder and sanding rolls
will break through the castings.
One thing we've learned about welding aluminum
for over 45 years is that if you weld it, it should be
re-heat treated. 4043 or 4943... Almost never is.
Dedicated S&S Special Application SA B1/B2/B3 heads upped the ante with bigger inlet and exhaust valves.
This is sort of coming to an end with the 2017
introduction of OEM M8 four valve motors. S&S is
making $12,000.00 M8 136" motors with revised heads. Price of
"progress".
