Jon,
Concerning the square washers, I would consider the "first principle" rule
of engineering. This is if something looks like it is going to help, it is
probably a good idea. If it looks like it is going to hurt, it is probably
a bad idea. This approach usually results in doing the right thing. I
would put the parts together in a way the gives the best function. If
everything seals well without the washers and it looks like it will stay
together, leave them out. If the washers are needed to hold everything
together, then find a way to make a good seal with them in there. If
something from the hardware store will do better than either of these, use
new parts. Without having the parts in my hand, I can't be more specific.
Any way that you end up with a solid airtight seal that gives a clean
airflow path is a winner.
Concerning using velocity stacks on carburetors. In almost every case
where an original design includes a sharp step in the airflow, someone has
developed an aftermarket part to smooth that transition. Smoother airflow
is better airflow. In a dyno test of an aftermarket intake system for a
new car, it was found to increase horsepower. Of all of the fancy
components in the system (bigger tube, bell shaped base for air filter,
free flow air filter, cold air intake) it was found that just using the
bell shaped filter base to smooth airflow was almost as effective as using
the entire system for about 1/3 of the price. Stacks will also probably
help idle because of the retained fuel fog at low airflow. One thing to
look out for is that there is sufficient clearance between the top of the
stacks and the filter cover. Anything less than an 3 cm is touchy and
anything less than 2 cm is probably unacceptable. Even with smoother
airflow you still need enough room for it to get through. I have heard of
people using a hack saw to resolve this type of issue but make sure that
the finished product results in a smooth air path. This usually involve
removing the middle of the stack and welding it back together shorter to
retain the mounting flange and the bell at the end.
Regards,
Bill Eastman
61 MGA who is getting to remain the daily driver for another week while the
body shop repaints the hatch on the other car.
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