318 with n.o.s. ???

That should work well, just be sure to use the new tune ups available. The new updated NOS tune ups use a Nitrous and Fuel jet that are the same size or the nitrous jet is bigger, depending on your horse power goals. and pulling timing is the key to not melting it down. I ran a 200 shot on pump gas on stock 340 bottom end, timing at 26 degrees total. I cant remember what jets I used, I also had a separate fuel line and regulator for the nitrous using one big fuel pump for the motor and nitrous and Y ed it off on inner fender.