installing nitrous again- is a 155 lph..

Yeah, the 155lph is not stock. Stock is like 88lph or some where around there. So, like everyone else said, you'll be fine running the 155lph pump with just the 75hp. shot.

I believe the Autolite 24s are the correct ones. But I'd still take a look at the stock heat range and just go one step colder for the 75 shot, possibly 2 steps colder if you ever end up juicing up over a 100hp shot. Yesh, gap them at .035 for the nitrous. But I've been told that you can open them up to .040-.045 if you have a decent aftermarket iginition system...which it looks like you do, running the Jacobs. And put the timing on 10btdc just to be safe. But again, with just the 75 shot you could probably get away with even 12 or 13 degrees. It's all about trial & error...see what works for you and what doesn't. But when playing with nitrous, I just always make sure I have everything within the "safe range"...plug gap & heat range, timing, bottle pressure, etc.

It's only once you get up around a 125-150hp shot, that you'll want to add an inline fuel pump like the tried and true T-Rex pump or something similar. I run a similar pump from MSD. You need more fuel volume and not just the pressure to compinsate for the incoming nitrous and extreme boost in fuel pressure over the duration of a full 1/4 mile run. Good luck and let us know what you run!