Wheelbase is a consideration, but certainly not the only one on designing a chassis and suspension for a canyon racer. Look at an 85" wheel base USAC sprint car on pavement, close in handling to Richard's 60/40 weight distribution Kart. A 5.0 Mustang just needs a bit of stiffening as Bill suggested (though I much prefer a weld in roll bar and ties). Chassis flex and soft springs and bars are what granny likes when she drives to Wal Mart, but certainly not the answer to what Shawn wants when he goes to play on Muhlholland...... The 5.0 also really likes a tower brace, a solid one not one of the showy ones, and bigger sway bars with poly bushings vs. the soft rubber ones that are so nice when granny goes to Wal Mart.....