32/36 Weber would be best, ran one on my slant six, when it would idle you couldnt even tell it was on. Idling around 350-400 Rpm. Since your using an early a body 63-66 it is very easy to adapt to the stock rod linkage. due to the way it mounts. on a 170 would run great.
Edelbrocks are good right out the box but not set up for a slant. If you plan to use an edelbrock 500cfm carb Use 0.83 Jets 058x052 metering rods, and .077 Secondaries.
Holley 390's Run lean on a slant 225 with stock Calibration on a 170 might be just right.
