Yeh thats how fast the gearing would allow the machine to go. The Tracker wouldnt be able to get up to that speed because of the dynamics. Well I am pretty sure anyway.

The tubes on headers are tuned for a desired outcome, just like organ pipes.  Different lengths and different bores (inside diameters) result in different horsepower/torque curves.

Equal length tubes even out the back pressure for each cylinder.  This is why some headers have screwy shapes.  It's not for looks.  The tri-Y design evens out the back pressure for a given firing order; especially important for shorter tubes.

Short and/or fat header tubes provide increased HP at higher RPMs.  However, taken to it's extreme, the HP peak will fall outside of the specs for the engine.  That's why a little bit of back pressure is a good thing.  It does you no good if your Zuk's HP peaks at 8K.  If your objective is to maximize your HP at highway speeds, short and fat is for you.

Long and/or smaller bore header tubes produce increased torque at lower RPMs.  If your objective is to gain power for crawling over rocks, long and thin is for you.

References for further study:
http://www.carcraft.com/techarticles/116_0312_test/index.html    (page 1)
http://www.carcraft.com/techarticles/116_0312_test/index1.html  (page 2)
http://superchevy.com/technical/engines_drivetrain/exhaust/0504sc_header/index.html    (page 1)
http://superchevy.com/technical/engines_drivetrain/exhaust/0504sc_header/index1.html  (page 2)