How much NOS?

You will run that thing lean if you try to spray it with the stock fuel pump in there.

Get the fuel system up to snuff and you can spray the hell out of it. Nitrous likes compression. You're no higher than 9.7-9.8 ish CR with the 58cc heads.

ASSuming you get it enough fuel and aren't detonating, you're really not in the danger zone with a stock pre-'93 5.0 bottom end until you're at a 200hp shot or higher, at least from what I've seen.

throw a 255 intank in it and hit it with a 100 to start with and get use to it... then go up from there.

id try the timing around 8* with 93oct and a 100 shot. might be able to get away with around 9-10 buts id do 8 to start and be safe.