My e-body regularly run 139+ with stock front end and close to 150 with some "persuasion". Never any stability issues. Check your calipers for drag, re-align car (front and rear). As mentioned, more caster will help high speed stability. Can either buy control arms or slide K-member forward. Also, preload setting in chassis can give you a scare if you just step of gas pedal at the stripe. Hope this helps. Good Luck