if you do use one you need to make a brace going from the front of the frame rail to the firewall. or http://www.martzchassis.net/page3.htm and also sub frame conectors.i have drove both a stock set up mustang and one with a mustang 2 kit the mustang 2 kit handled worse but the car it was in was heavier and had a 4.6. but im compairing a 68 coupe with a small block to a 67 fastback gt500e clone with a 4.6 its a good 600 pounds or more heavier.