So i actually ended up getting an RPM transmission for this car and they claim it’s good for 800whp, they make even higher “stage” trans’s though if you plan on making more. In my opinion the 4 speed gets better the more power you are making. Since the gear ratio is naturally more spread out in a 4 speed you are going to use more of the rev range than just the power band, but a high stall converter can help to keep it up there