Adam, my feeling is, if you have to build the lower end anyway, go the biggest you can for the same money. In my builds, they all get align honed with new bolts/studs. They all get internal balanced. So money wise, it's a toss up between spending to have a factory crank cut down ($250-300 depending) and the cost of buying a new one outright ($280-330). I havent seen the same QC issues witht he small block cranks. Not sure why, but they always seen to be pretty good, even the cheapies. So I use them when possible. In this case, I like lower stalls, and my customers cruise a lot in the cars. So it's about milder gearing and stalls under 3K. So yes, the 4" arm is to lower the power peaks' rpm, and to flatten out the torque peak during the crutial 3000-5000 range. Those are mid sized 4" engine cams, but the heads work well with them. I'd expect just over 500tq, and the tq peak being close to flat from 2800 to 5000.