Hi. The carb is plenty big for just about any street driven 440. When you say built, what do you mean? For NOS you need to have at a minimun hyper pistons & preferrably forged rods & 4 bolt mains. Your talking about putting allot of extra stress and heat on the bottom end. Compression is another consideration. Although a 100 shot of NOS is not that big compared to what is available, you really need to make sure your mill is up to the extra load you're asking it carry. Is it a fresh build or have some miles on it. A tired engine won't stand up to even an occasional shot of NOS. Also don't forget that you'll have to rejet your carb to prevent a lean condition. Let your plugs tell you what is going on inside after each run until you get it dialed in. Hope this helps.