Well, I built one with a 520ish solid. It idles smooth as glass with tons of vaccum...I admit now, the cam is too small...lol. A good rule of thumb for 4" strokes is: hydraulics start at 235°@.050, with 245 being a nice performance one. Solids Start at 240°@.050 with 250 being a nice middle ground. Head choice is huge. Better heads work well with smaller cams. Smaller ported iron heads will want more cam to make up for the less flow rate. Another thing is, on Mopar small blocks, you will lose about .025" of lift just from bad pushrod angles and factory rocker geometry.