Can i run a 50 shot of nitrous on a 351w with hyper pistons, stock 351 crank. Engine is rebuilt with new everything, edelbrock top end kit with 650 carb.

 

sure, your fine w/ 150 even

 

I called my my machine shopwho built the engineand they said I shouldn't do it, the pistons are kb. Whatare the chances of me blowing something out with a 100 shot.

 

a 351 stock can handle a lot trust me!

 

A lot of shops "freak" when they here the word nitrous, and way back in the day, there was a fairly good reason to.
There was a time when I wouldn't have used it if someone had given me a kit for free.
But those times are long past.
If your worried about it, then start off with a 50 shot.
Find some stretch of road and give it a wide open blast thru the gears.
Shut off your engine, and pull off of the road.
Pull ALL 8 plugs and give them the eyeball.
If there's no signs of pitting, glazing, little silvery specks on the porcilon,
[ white part, my spelling sucks] then up the jets to a 75 shot and try her again.
Now, to be extra carefull, when you go to the 100 shot, you should put it on a dyno to make sure your a/f ratio is okay.
A 12.5 is about optimum.
You can also check to make sure your timing is stock, and hasn't had any advance put into it, which will hold you back from a bigger shot.
If your timing is good, go to a step colder plugs and whack it with a 125 shot, or even jump to a 150, if your fuel pump is up to the task.
Your 351 will make good use of the nitrous, and when done right, will suffer no ill effects.

 

50 shot is no problem for 351w!

 

125 wet - max imo - unless you dont care if it blows - then run a 175-200 and keep your fingers crossed

 

50 is fine, a general rule of thumb is no more than 50% of your engines power stock. after that you are gunna need forged internals to handle the heat, that and new fuel system