I have a built 383 sbc carb'd with forged internals, Dart heads and a custom nitrous grind cam. Its got 9.25:1 compression. I'm installing a NX plate kit. I wanna run a 100 shot. I know I need to retard the timing, get colder plugs and add fuel pressure. I just want to know how much timing I need to pull back. And How much fuel pressure to add.

 

2 degrees for every 50 hp of nitrous.
So 4 if you run 100 hp shot...
Most people with 350's are running 150 shots (6 degrees total). with stock internals...
Be sure to add a fuel pressure safety switch so that if the fuel pressure drops, it cuts off the nitrous so it doesn't run high nitrous / low fuel / boom...

 

How much fuel pressure should I add? And could you send me a link to a fuel pressure safety switch so I know what one looks like?

 

Don't know much about carb'd stuff / pressures, mostly TPI...

https://www.google.com/search?q=nitr...tch+carburetor