Here are a few formulas.
http://www3.sympatico.ca/big-d/polytek.htm

there are calculations around, search for them on google. And you will probably need to do some trial and error. This long length for torque short for power is all fine but the big gains are in pulse tuning to help force charge into the engine. This will work best at a specific engine speed and will be working in reverse ie trying to force charge out of the engine at another engine speed, you can see this as a fuel mist coming out of the carbs at certain rpm on some cars without air filters.
All the same goes for exhaust, hence tuned length headers which are a lot of work to make which is probaly why true tuned length headers are expensive and rare.
fwiw the Honsowetz bible says use 32in primaries and an exhaust pipe at least 72 in long.

revs easily to 8000

what rpm are you hitting? that has a lot to do with how the setup will go.

any suggestions on what lenth for flat out quarter mile

Correct!

ok this is for the ram tubes that fit in front of the carbs
and not the headers that fit on the head
is this correct
thanks

Generally trial and error minnesh, the shorter the tube the more top end it will give, longer more torquer, just like longer runners on forklift inlet manifolds give more torque.

gentlemen,
imn full of questions this week

40mm suideraughts on an a worked drag a14 normally aspirated motor
what would u guys recomend the size of the ram tubes should be
is there any calculation to get the correct size or is it just trial and error
thanks

thanks guys
thats great info