I have a stock short block 400sbc with cast dished pistons(9-1 comp) and stock rods.
I have shot a 125hp dry shot last fall and used 110 octane fuel, also have non-projected plugs.
I would like to spray a 150 shot this season.
My plugs read a touch on the rich side so my tune is safe.

Am I pushing my luck?
Would higher octane fuel give me more safety? I'm willing to use 112 if I have to...

Bump?

Hey Bro, good number's in your sig. IMO your playing with fire using a dry shot system, but if it works for you then go for it. You'll always want more, so I can see you going straight to a 175 shot because an extra 25 shot is not that much. Good luck though!

Yes!
Nitrous is addicting! More is better! lol.

I blew my last engine with a 175hp shot, so I'm not going farther than a 150shot until I get better pistons.

How is more fuel being added with the shot.

As long as tune remains safe you should be ok although stressing stock block internals is more of a concern regardless of octane. Octane may save engine from detonation abuse but does not save from forces and heat generated by the shot itself. More you hammer pistons rods and bearings with spray it will eventually wear out. Nitrous is hard on motors

Its a dry shot, so some of the bottle pressure is bled off, then pushes against the afpr, then ups the pressure to the injectors.
I have 36lb injectors (yes too big I know for n/a), so I have room to do a 150shot.

N/a I'm running about 30psi thru the injectors. More obviously with a 125 hot.

And yes, more octane won't be any easier on the stock block internals. I'm just hoping that more octane can save the engine from detonation.

It should help but 110-112 should be enough with any of those shots. As long as you control the fuel pressure right and its consistant, the timing will make the difference. You shouldnt detonate on pump gas let alone 110+ oct. just keep timing out and make sure plug heat range is low enough while tuning the initial spray.

I used a 150 shot on my L98 stock. I used 100 octane at the track. No problems at that time

FWIW,
I've been running .052 to a .063 nitrous jet (150-175ish hp) through a wet plate with a miniram(which I know is dangerous) for almost 20 years. ZZ-3 with cheap TRW forged pistons. I go through less than a bottle a year though. Usually with 93 octane and so far, so good! I'm pulling 4* with a msd digital 6 nowadays.

You need to run a wet shot if you want your motor to live. A 150 wet shot on a good tune up will work on a stock motor for a long time. The only reason to run 110 is to keep the timing. I personally ran a 150 shot on my 406 for two summers. I pulled 5 degrees of timing and had a good tune up. And by tune up I don't mean plugs and wires. I mean jet sizes. I had a wide band though so I could adjust my fuel jet to correct my air fuel readings.