ok so i have a chance to buy a all forged 400 s/b for $2,500 my brother told me that with my fastburn heads the comp. ratio would be around 11 and a half so is high compression bad for nitrous?

From what i heard NO2 like compression. so that would be a good thing. just gap your rings right and step down a heat stage in plugs and you should be ok

11.5 isnt high at all really. Just make sure the proper timing is pulled when spraying and you'll be fine. you most likely WONT be able to run pump gas on this motor though without pulling ALOT of timing to combat detonation. The ring gap should be a little bigger if you're running a big shot, but around 100-150 you should be fine with a normal NA ring gap, unless of course you are making it a dedicated nitrous car then i would suggest opening that gap up some.

Also don't forget to step up to race gas or use octane boost depending on the amount of the shot. Make sure the fuel system is up for it too. Don't get too greedy either, if you pay attention to timing and fuel delivery you get lots of and no

wow thanks guys thats good to hear