Sounds like you've got it covered.........so to speak.
Just to review:
Primaries the exact ID of the exhaust liners and exactly the same length to
the collector. If you cannot match the ID exactly then make the
primaries just a hair bigger. Collect at a shallow angle. (longer
collector) Broader torque band. Steeper angle (shorter collector) more torque
but narrow band. Collector outlet 2 1/4" to 2 1/2" into a long megaphone to tail
pipe size. Try to split the included angles into the collector.
A 3" pipe is fine but not for leaving the collector. The tuned length will
end there otherwise. Just take a long dart out of the pipe and end the collector
with a 2 1/2" ID.
Unequal header lengths and or entry angles make a very sad sounding engine.
Ideal shapes and angles make for a sweet sounding engine.
Loud but sweet.
Lynn E. Hanover
In a message dated 5/29/2012 2:14:09 P.M. Eastern Daylight Time,
echristley@att.net writes:
My
exhaust is encased in a .015 stainless box down to the end of the
collector. The down pipe and muffler are exposed,
and I see where it
is blistering the belly paint already. I'll be wrapping more of the
exhaust in the thin stainless.
I will also open the stainless box up to
allow some blast air through. First I have to change that down pipe from
1.5"
dia to 3". I can't seem to get above 5100RPM, and I think
exhaust backpressure is my
issue.