ZZ3 and TBI

[Gary Derian]

According to Lingemfelter, the pushrod guideplates in factory aluminum heads
only hold the pushrods during factory assembly.  Their slots are wide and
the plates are not hardened.  Also he is very clear in his opinion that
roller tips don't roll anyway so either use stock rockers or those with
roller fulcrums but not roller tips.  Factory rockers now have roller
fulcrums to reduce friction and oil requirements.
Gary Derian <gderian at cybergate.net>

>John Zarli wrote:
>
>> I am using Crane narrow body "gold race" rockers.  Note that while all
<1988
>> heads may use a stamped version of a self aligning rocker arm, not all
late
>> model heads really  require them.  My cast iron truck heads have a slot
in the
>> cast iron, as opposed to a large hole.  I DO need the narrow body
 center bolt
>> valve covers).  For some reason Northern Auto Parts carries these at a
lot less
>> ($240 vs $300) than the self aligning type & if you moved up to a
performance
>> head that used guide plates you still have the right type of rocker arm.
>
>Limiting factor with "slot" style heads is pushrod "excursion" - This
>means that
>the pushrod moves back & forth in the slot as it goes up & down.
>Excursion is a
>function of cam base circle, cam lift, pushrod length, rocker ratio, and
>the actual rocker dimensions. If your particular combination of parts
>does not produce
>interference between pushrod & slot then I know of no reason to use
>guide plates.
>(Please enlighten me if you know different). I have had good results
>with simply
>elongating the factory slot to accomodate the parts used.
>
>Jack.
>
>BTW, Comp Cams stamped rollers are money well spent for stock and
>close-to stock
>apps. Reduces guide wear to zip. No financial interest in same.