Yep...
the good doctors own about 6 LBC's and
Marty definitely is into this stuff.
For clarity's sake, the Pierce alum head with
stock valve sizes is said to flow as well as
a Longman GT6, which is a modified version
of the stock cast iron item. Cost for each
is pretty much the same though.
The advantage of the alum head is in it's
ability to run a higher compression ratio as
compared to the cast iron item.
MiniMania offers the stock Pierce along
with a version offering the larger 1.4
intake valve for a bit more.
The advantage of a true 1.347 (offset bush)
rocker on even the stock motor can be seen on page 297(fig. 11.7) of Vizard's
bible,
in terms of useable street torque with mild
factory cams & stock valve sizes. The fact
these can be used on the stock pedestals
and shafts is a real plus as well. Really holds down the costs. AND...it's got a
roller tip. Very nice alternative to the more
expensive 1.5 set-ups.
Gotta check for coil binding at full lift though with valve springs made for the
stock factory rocker ratio, I would think.
But as I "read it"....
it seems with mild grinds and
stock valve sizes, that
the higher lift rockers pay off mostly
in terms of
torque below 3k and HP above 4.5K, whereas with hairier cams and larger intake
valve sizes, the higher lift pays off
in the upper end only, probably due to
decreased port velocities toward the low
end?
Should be more or less the same with 1.5's
I would think, maybe with a little more
"grunt" but not by much I would think?
I bet the offset bush roller 1.347's get one
about 90% "there" without the additional
expense of going to 1.5's.
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