Interesting....tuning the intake length DOES work BUT you have to find the right length...I have done some experimenting but have been busy lately so my project remains uncompleted....FWIW a 24" intake on a HT engine gives great low end off idle BUT above idle it just dies on power.....I was starting with a 24" runner and was going to trim off from there....
Good luck and if you decide to tinker...please keep us informed....
generally the rule of thumb, at least for cars, is the longer the intake, the more low end torque but less top end hp. Shorter intake yields less low end torque but more top end hp.
exhaust - more restrictive = more tq low, less hp high. more open = less tq low, more hp high.
edit: and that's a fairly informative article. Someone needs to make all those measurements