WET or DRY?

You might be ok with the 24s. I run a 306 with the mods in my sig. I too use the 5115 dry kit from NOS. I use 24lbers. with a 150 shot. I have a 155lph intank pump and a 200gph MSD inline pump. As long as you are pushing plenty of fuel volume...you'll be ok. I think the 255lph your are getting should be sufficient...but don't quote me on that. But the dry system comes with the fuel safety cut off switch if the fuel pressure drops below the desired 80-85 psi. to mix with the juice...then the system will shut off the flow of nitrous. My motor is no 347...but if you are going to keep it mellow...between 75 & a 100 shot...I think you'll be fine. Just keep an eye on the plugs...and a timing retard couldn't hurt either.