My 383 has cast pistons and short rods with edlebrock performer rpm heads cam & intake. I'm assuming it's just shy of 400 hp. Will a 100 hp shot of NOS kill it?

 

If it wasn't for the cast pistons, I would say you would be ok. Unfortunately, cast pistons do not handle any kind of detonation, or preignition. They tend to break easily.

 

I bought a Chevy High Performance magazine because of an article regarding NOS. They took a stock (cast piston) bottom end 350 small block chevy and put a decent cam and some head work. Basic results were:

Stock: 310 hp
100 shot : 405 hp
200 shot: 521 hp
325 shot: 599 hp
425 shot: broken pistons

Hmmm 375 + 100 might hold up!

 

Yeah.. I just finished reading that last night..
"purging the spray at idle"?? WTF were they thinking??

You may get away with it for a while, but the problem with cast is, all it takes is one time.. they just are not at all forgiving like a good forged piston is.

I've seen many a Ford guy throw a stock 5.0 motor in, and spray the dog s__t out of it... they all eventually die a spectacular death.. just depends on how much you want to replace when it does go BANG!

And it will!

 

If you no what your doing with nitros you wont have a problem.

 

I read that article also. very impressive. Also very stupid of them to spray while idling! Kinda makes you wonder how legitimate their tests are!!!

You will be fine with the 100 shot or even 150 shot. Just make sure you install a fuel pressure gauge and monitor it closely while spraying! 7psi is ideal

Heavy

 

I could replace the pistons and rings only. The engine is sitting in the subframe which is currently removed from the car. Any guesses as to how much it might cost to do just that? The engine has about 20k miles. What I don't want to do is turn a supposed small job into a complete rebuild and rack up a $1000 bill.

Hmmm heads off, pan off, rod caps, press pistons, hone

hmmmmmmmmm

 

It sounds like your engine is still together. If so, it will be too much work to get to the pistons and rings so you might as well do a fresh rebuild. All the machine work should cost less than a few hundred.

Don't forget about the fuel pressure!

 

you could not hurt a 305 with a 100 shot if you tried. I have run many cast piston 350s with a N.O.S. Powershot (unadjustable 125 shot system) and have never had a problem. I have run the system with the fuel solinoid disconected for over a year on the same motor and not problems. I even had 305 heads on it so it was 10.1 compression. The General rule of thumb is with most any V8 up to a 350 you are safe with up to a 125 shot. With a 400CI motor or larger you are safe with a 200 shot.

As for the 5.0 guys... from 88 - 92 those motors came from the factory with forged pistons so they could get away with spraying the hell out of them with stock bottom ends. F*rd had their **** together then. put forged pistons in the car from the factory and put a strong rearend in it to handle the power. GM could have taken a hint from them there.

 

slap some different pistons in it and you should be alright