Bryan,
This last weekend, Joe Mondello spoke at the NW Banquet revealing gobs
of info on this subject. At one time it was thought that bigger was
better, but that myth has been abandoned long ago. Joe talks about a wet
flow bench that gives lots of info on the air induction, including what
happens in the combustion chamber.
The appearance of the restrictor plate in Nascar has given a great deal
of info in this area. The heads I have were purchased from the Sabco
Team. They were restrictor plate heads. The intake runner was reduced in
size by about 1/3 with epoxy. I understand that two things helped to
overcome some of the HP losses in the restrictor plate engines were
higher compression and higher intake velocity. Some of the same thinking
is also used in getting the exhaust out.
If you remember the Ram Induction that Chysler was using in the early
60s, you will note that their design was changed from the original long
rams to shorter ones for high performance engines. The long runners gave
gobs of torque in the lower rpms, but sacrificed hp on the top. The
shorter runners moved the torque up the rpm scale. The idea behind this
system was to use the momentum of the air movement to stack air against
the intake valve while closed. This gave a more dense charge when the
valve opened.
A Muffler Shop friend, Dave Hooper, and I did some experimenting with
the exhaust system on my roadster in the early 60s. We used four 2"
pipes, two on each side tying the cylinders in pairs to each pipe and
extending them back above the rear wheels. It added a great deal to the
low end torque. However, as in the case with the Chysler setup, it
suffered on the top end. Just some food for thought!
Tom, Redding CA - #216 D/CC
Bryan Savage wrote:
> About 30 years ago a guy in L.A., Jerry Branch, said that air flow QUALITY
> was more important than quantity. And he proved it repeatedly.
>
> Bryan
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