Start here:
http://www.bgsoflex.com/intakeln.htmlYou can also use the posted chart as a good starting point. Length is dependent upon cam timing but with short/small stock cams this will get you close enough.
Intake length is the ENTIRE length form valve to atmosphere so you need to know the intake port length and carb length.
Trust me in that this will make a huge difference, especially right in the middle.
On the 130% VE question... 1.30 x 14.7 PSIA - 14.7 PSIA = 4.4 PSIG
That is obviously a Best-Case scenario but I have seen dyno tests where they measured 3+ PSIG on the intake side with tuned runners.
My inspiration was here:
http://www.phaedrus.me/id158.html