nos on a 318

I don't know how you would run a dry kit on a carb car? Injected cars spray nitrous only into the intake manifold, while simultaneously spiking the fuel pressure to spray more out of the injectors, that doesn't really work on a carb car.

Anyways,

Most engines can take 125-150 if they're in otherwise decent shape. I think you'd have fun with it.

I'd say do it, but do it right. Start with the smallest jets and read the plugs as you do bigger shots. Running the right plugs (colder heat range, non projector electrode, not Champion) is important as well.

Intake manifold makes a difference too. I'd look for one of those old timey Holley single plane intakes (Street dominator I think its called).

Good exhaust flow is important to power production, as you've got a lot more to get out of the chamber.

Lean and/or halfass tuneup is what kills most nitrous motors-remember, the FUEL makes the power, not the nitrous- BUT there are other dangers too.

Nitrous creates enormous cylinder pressures, much more so than turbos or superchargers, and a cast piston or 40 year old bearings are only going to take so much. One way to help is to shift at conservative RPMs.

Consistent bottle pressure is the secret to success. A good bottle heater is a crucial part of a nitrous install.

Historically speaking, NOS kits are jetted very conservatively. Nitrous Xpress kits are more aggressive.

Run distilled water instead of antifreeze (always a good idea for a track car). If you blow a head gasket, antifreeze will eat the bearings in a hurry. Cools better anyway.

Have a fire extinguisher in the car.

Last but not least, even though if you do it right, nitrous can be a low risk affair, never put the bottle on anything you aren't willing to destroy.

Steve