Steve You wrote:
> Tim,
>
> What is a "stub stack", and will it fit the stock Tiger air cleaner
housing with
> the correct K&N main filter?
>
Steve and listers,
Maybe it is yet another canadian innovation like the 6-bladed fan!
Short answer....NO!
Long answer Maybe or why would we want to.....
A K&N stubstack is a phenolic resin piece that is shaped to fit inside a
Holley 4-barrel carburator. The intent of the piece is to streamline the
rather poor aerodynamics of the Choke housing area. As this piece hangs out
of the top of the carb it would decrease clearance and thereby reduce
airflow to the carb with the limited fixed distance to the top of the
aircleaner lid. With the old Morroso and K&N airfilter housings they adopted
a low profile design and permitted you to use both the low profile airfilter
and the stubstack if you used a 3 inch tall filter element. This maintained
the minimum 1 inch clearance to the top of the airfilter lid and did not
impair engine breathing as evidenced by our dyno runs. I do not yet have a
Holley 4-barrel on my car and Theo is currently running something like a
Carter or an Edel-broke so I can't comment about the clearances yet but it
appeared to me that there is insufficient distance to use it as the lower
aircleaner plate does not drop down around the carb and the air filter
assembly overall has about 5/8" clearance to the factory 2-barrel housing to
the center of the aircleaner lid depending on how aggressive you are when
torquing down the hold down screw. The choke blade is even closer at about
3/8" or less when open. I can only imagine the amount of turbulence our
little 260 air pumps are generating as the air "cavitates" past the edges on
the choke housing with such a small amount of clearance. The limiting factor
for lid to carb housing clearance is the ouside edges of the aircleaner lid
with hood interference/clearance but the center of the aircleaner can come
up about 1" on the 2-barrel configuration and by all reports it would be
similar for the 4-barrel set-ups but might be a little less.
Rather than tell all of you what you already know the car is likely starved
for air at high RPM (5000+) with both the stock 2-barrel as well as the
4-barrel on the primary circuit, although with the 4-barrel there willl be
some gains due to the secondary circuit but it may be because the primary
circuit is so inherently restricted and the secondaries are relatively
unshrouded. The clear fix to me is to purchase one of those race/performance
carbs (Barry Grant sports Claw) with the choke horn milled off to improve
the airflow over / around the choke housing or cut up the factory aircleaner
assembly to raise the center to obtain the 1" clearance to the choke horn.
I will likely go for the milled carb approach but will do my own and I plan
on running the new RPM performer manifold for good low end torque with
decent mid range. Since I am considering a powerplant with more cubes this
carb to cleaner clearance is bound to be an issue for me....unless Theo
convinces me to use his fuel injection system.
Long winded, Eh! It,s lunch time and I had 12 minutes.
regards,
Tim Ronak
B382000680
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