What do you guys feel will be the best gear for my setup. I am planing a tranny rebuild with a Vigilante converter. Would I see a difference between the 3.42 and 3.73's?
Mods are in my sig. All my intake stuff is port matched.

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1991 Z28 5.7L, Edelbrock headers, Eldebrock intake base, SLP runners, GMPP 1.6 roller rockers, Hypertech Theromaster chip w/ 160stat, Accel 300+ race wires w/sleeve, MSD coil, relocated MAT, TB bypass, K&N's in gutted airbox

 

I run 3.27s behind a tight Vigilante. If it were my choice I'd go 3.42. The Vigilante will provide great torque multiplication off the line, lessening the need for deeper gears. Once you're moving the extra slippage of this converter will yield a similar engine RPM to MPH relationship to 3.73's with a stock converter. Once I shift into third my engine RPMs are about 300-400 RPM higher at a given speed than before the Vigilante. 3.42's will provide an extra margin to prevent overrevving on the top end if you're really hauling (108+ MPH in the quarter). Not a problem for me.

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89 Formula 350, Accel Tri-Ys, 3" SLP, chip, Jacobs, SLP cold air, Probuilt tranny, Vigilante, 3.27s, Spohn torque arm & LCAs w/brackets, GW Subs

 

I dont know what powerband your car runs best in but I would go with 3.42's if I were you. If your car can pull past 5000 rpms then you can go for the 3.73's..and then you should also be lookin at a good pair of drag radial or slicks for the track.

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88 Iroc 305 TPI 5 speed
Performance Resource Chip, Flowmaster American Thunder cat back exhaust, B&M Ripper shifter, MSD coil, TB bypass, TPIS MAT relocation kit , TPIS 170* t-stat, Richmond 3.73 gears, March Power & Amp pullies
First time at track: 14.781 @95.13 mph , & 2.204 60'