What does this "425hp 351w" have done to it?
You can bolt up any tranny that fits a 302.
Gears.....well that is a can of worms cause it depends on what you want from the car so there are plenty of choices out there.
Don't forget to address the chassis and suspension.
2016 VW GTI 2.0 Turbo
1989 Sonic Blue LX Coupe, 349 ci, TW heads, TFS Track Heat Intake, 75mm Accufab TB, 80mm ProM, 30 lb. inj, TKO, 3.73, 31 spline w/ TruTrac, MAC 1-5/8" LT headers w/ H pipe, Flowmaster, electric fan Moates QH
391 rwhp & 424 rwtq...Mustang Dyno 11.5@122mph