Okay – your rear end is geared too high and you probably need a bit more converter to take advantage of the RPM range.

If you have 315/35R17 drag radial tire (diameter = 25.71) with your 3:08 rear end you’re at 3.36:1 equivalent as the Nittos are smaller in diameter than your stock tires. A stock TH400 1st gear is 2.48: 1 so your launch is at 8.33:1 (3.36*2.48). Your buddy’s actually hurting his launch with the 275/60R15 Nittos (larger than the stock 215/65R15 on the Camaro) and he has an effective rearend ratio is 3.07:1. However, the Tremec T-5 first gear is 2.87 so he’s launching at 8.81

When you hit second the TH400 is effectively 4.97:1 (1.48*3.36) but the Tremec had two more gears so his second is 5.80:1 (1.89*3.07).

In third, you’re at 3.36:1 – your buddy is at 3.93:1. If he hits 4th, he will be at 3.07 – but my thought is he’s smoking you in his second and third gears.

Going to 3:73 gears and 3400 stall will probably put a big smile on your face and the Camaro in the rear view mirror
Glenn