I stripped the mounting screw on my CPI Spider injector replacing the fuel pressure regulator. Can I re-thread it or do I need to replace the whole spider?

 

Assuming the hole is open all the way through, you could chance putting a long bolt and nut along with a lock washer or some thread lock, but if it ever comes loose just knows it's going straight into a cylinder... I suppose you could thread in a larger diameter screw, will probably have to ream the hole out in the plate that goes over the pressure regulator to accommodate. I believe it's just threading into plastic? If you use a self taping screw you should be able to create some new threads, but go slow and try to thread it in without the plate in the way first, maybe a turn at a time and then backing it back out some, and repeat until you bottom the screw out. Most plastics, even ones designed for use in the application, will get pretty brittle over time in a gas rich environment and being put through countless heat cycles... Try to thread to quick and you may put too much stress in the plastic and crack the assembly where the screw hole is, in which case yeah you'll be replacing the injector assembly...