Been messing with engines for a long time, but never
delved into aftermarket heads (and adjustable
valve-train geometry) until recently.
Just set up a set of TW170's on an 86 5.0
(that I bought new, first time heads ever off it)
and came up with what I thought was a pretty
good pattern, .043 width, slightly offset exh side
Previously, I had got a set of GT40X heads a while ago for a mild build
for my dad's hot rod (mostly a show car) that
uses a mildy built AOD and never sees much over 5300RPM.
Ordered a set of 1.6 RR and went about checking
pattern for PS length. Could not get anything
I considered acceptable. All testing was done
with TF's adjustable pushrod and a stock lifter set solid.
I ordered a different set of 1.6's and tried some
no name brand, 1.7's I had lying around. These
are the best patterns I could get. They are
all WAY off center to exh side.
Just bolting all 3 sets of these down with no spacers, yielded patterns of .132, .108, .132,
I figure this is what the average guy who has
a hard enough time even checking for lifter pre-load
is going to get for pattern, as I assume most don't
even know or care what the pattern width is.
Talked to Harland Sharp and they said their pedestal
1.6's have the same basic geometry that everyone else
has, but had chevy and dodge pedestal's that had
shorter fulcrum to roller distances.
After messing around for quite a while with those,
ended up with a best of .071 width, .013 offset to exh side,
using the dodge 5.2/5.9 HS 70036A 1.6 rocker.
I did have to use a total standoff of close to an inch,
vs the average pedestal standoff height of around 6 tenths.
I'm a bit concerned with the height I needed for
the HS rockers, as I don't know if that will affect
rocker side load and/or how square the roller is to tip
@ "higher" RPM (and the fact I will have to get really tall
valve covers, space up the intake, and maybe not fit under the hood).
So I guess my question is, for mild cammed, low RPM
street motor does it even matter? Have to be thousands out
there that bolt these rockers on and go only worrying about
lifter pre-load (let alone the millions of motors that go 150K
with stock stamped rockers and I'm told that "pattern" practically
covers the entire valve tip??).
delved into aftermarket heads (and adjustable
valve-train geometry) until recently.
Just set up a set of TW170's on an 86 5.0
(that I bought new, first time heads ever off it)
and came up with what I thought was a pretty
good pattern, .043 width, slightly offset exh side
Previously, I had got a set of GT40X heads a while ago for a mild build
for my dad's hot rod (mostly a show car) that
uses a mildy built AOD and never sees much over 5300RPM.
Ordered a set of 1.6 RR and went about checking
pattern for PS length. Could not get anything
I considered acceptable. All testing was done
with TF's adjustable pushrod and a stock lifter set solid.
I ordered a different set of 1.6's and tried some
no name brand, 1.7's I had lying around. These
are the best patterns I could get. They are
all WAY off center to exh side.
Just bolting all 3 sets of these down with no spacers, yielded patterns of .132, .108, .132,
I figure this is what the average guy who has
a hard enough time even checking for lifter pre-load
is going to get for pattern, as I assume most don't
even know or care what the pattern width is.
Talked to Harland Sharp and they said their pedestal
1.6's have the same basic geometry that everyone else
has, but had chevy and dodge pedestal's that had
shorter fulcrum to roller distances.
After messing around for quite a while with those,
ended up with a best of .071 width, .013 offset to exh side,
using the dodge 5.2/5.9 HS 70036A 1.6 rocker.
I did have to use a total standoff of close to an inch,
vs the average pedestal standoff height of around 6 tenths.
I'm a bit concerned with the height I needed for
the HS rockers, as I don't know if that will affect
rocker side load and/or how square the roller is to tip
@ "higher" RPM (and the fact I will have to get really tall
valve covers, space up the intake, and maybe not fit under the hood).
So I guess my question is, for mild cammed, low RPM
street motor does it even matter? Have to be thousands out
there that bolt these rockers on and go only worrying about
lifter pre-load (let alone the millions of motors that go 150K
with stock stamped rockers and I'm told that "pattern" practically
covers the entire valve tip??).