I have a factory 88 5.0 convertible and I’m installing BBK ISS. It’s a whole kit that comes with a 75mm.
my question is do I have to change the MAF and 25lbs injectors.
Wow... haven't heard of or seen one of those in 10 years easily.
Yes, you should change the MAF so it is at least as large as your TB. If you're already running Ford 24 lb/hr injectors or larger, you should not need larger ones again unless you decide to add forced induction.
What method are you using to tune this combination?
I had one of those probably at least 10 years ago they are notorious for fuel line leaks. I can not speak for that because after i installed it shortly after i built a new motor and changed the intake. Do your research and good luck.