I want to make my convertible go 14s

[ziggy_2k]

I have a BONE stock 1990 LX 5.0 5spd. I can get 15.2s all day long with my cheap rubber. From what I understand the magic number is 13.99 before you need a role cage. I don't want a role cage in my convertible. You may say why even bother than. Well My Uncle has a 1968 Pontiac Lemans with a 350 He is barely breaking into the high 15.s and it really bugs him that my mustang is faster. I know over the winter he is gonna modify his engine so I want to be able to continue to beat him. He had a 68 GTO that would go 14.3 till the cows came home. I love that I'm faster now. I don't want to do things like gears, nitrous, tires or underdrive pulleys. My mustang sees some highway miles and It has a stereo system. I want to do things that will add more power.
For sure I want subframe connectors and a shifter otherwise all the power will be lost. I would like opinoins on which are best. I'm in college so I'm on a limited budget. I'm hopeing not to spend more than $1000.
Thanks for your time.