[1968FastbackN20]

Most cast pistons cannot handle more then 100hp shot of N20 without ending up in your oil pan. For $1500 I would look at a intake, carb and head porting. Make sure these all match each other. You may want to consult your local machine shop as to recomendations. Magazines have decent info but it always seems the company paying the most for advertising or giving free parts gets the most press. Not necessarily the best parts. Just my .02 worth.