is a 50 shot of nitrous too much for a motor with 112000 miles. ill only b on the nitrous once in a while not often at all.

 

if the motor is in bad shape already yes. if its got good even compression and doesnt use oil than its fine. 50 hp isnt anything. i figure you will use it 2-3 times before you up the jets to somthing noticable. if you have a wet hit (gas and nitrous) than 150 is safe on a 85-91 mustang (hell if you build the fuel system up to handle it 250 would be safe). if you have a later with hypers i would run 100 or less. if you run a dry hit dont run above 100 if you can avoide it, the stock injectors will have a hard time keeping up.

 

My motor has 122000 miles on it and I grab a 125 shot a couple of times a week.......

 

u can run more than a 125 is the motor is tuned right

 

As mrbigshot said it all depends on the condition of the motor, and you'll get bored with the 50 shot real quick.
I ran 125 shot on a stock '88 5.0 motor with 194,000 miles on it! I wouldn't reccommend more then 125 unless you have a high flow fuel pump, after market ignition, colder plugs and a wide band. I know people have but the risk goes up.