I know of a set of heads with welded larger exhaust ports than stock.
They flow more CFMs than Steg's.
Its not true that a SC port with extra CCs will not flow as Much or
as fast as a smaller port.
Most gasket matching is a waste because people do not take the
time or proper steps to assemble the motor .To take full advatage
of a gasket match.And why gasket match every manifold head port
to the gaskets.Hasent any of you ever heard of cutting the gasket.
To raise air flow entering a port.Then gasket match.
For a street motor or daily driver.A gasket match is just fine to do.
if you know how to do it right.You just don't lay the gasket on a
head or manifold,header.The gasket is placed in a consistant manner
to make your mark to even start the porting.You should use dowls
or shimed bolts in all bolt holes for matching gaskets.You then use
the same machined dowl to place gasket on the head,the glue,
then slide manifold on to gasket & head ,Then remove dowl and
install one bolt one at a time.
It takes more than just a good head porter.You also need someone
that knows how to assemble in a blue print style.To take full advantage
of the port work.
You cannot list what needs to be done for a proper port job.In this
post or even be able to write it down in one week.Any time you start
a post about porting here .The nay-sayers will come out of the wood
work from every direction.
And a flow bench is not a tell all or solve all porting tool.Its just one
flow tool to use.
The short side radius in the exhaust port of a SC 3.8 head is one
of the largest problems in the exhaust port.Take the exhaust valve
out.Then rub your finger in the port across the short side radius.
you will find that it has a sharpe feel.this should be rounded.Some SC
ports exhaust floor is so low,That the seat is above the exhaust
short side radius.If your head casting is like this,I would get another
set of head casting to work with.Or pull the seats and do a weld
build up,to form a short side radius.Then raise the roof just above
the short side radius on the floor.The same amont as the shot raidius.
For a street motor this should be about 80%+ of the size valve.For
a higher RPM motor take it up to 90+.
Randy