"Hard to start/no start" on 8 cyls and you suggest it'll start easier on 7?
Is that like testing a 9 volt battery on your tongue?
What, you don't believe in miracles?! <jk>
I "think" it has to do with a terminal inside the distributer cancelling or shorting out or something like that. Maybe
@Schurkey can explain it if he knows what I'm talking about.
I agree about the moisture: I suffered from a crank/no-start on my old '99 1500 4.3 Vortec for a long time. My issue was guaranteed to occur when it was damp/raining/humid. I never figured it out, but suspected distributer doing something similar to what I mentioned above; I had gone through and changed/checked all electrical components over that time. The only part I wasn't really able to check was the distributer, which had been replaced once. Towards the end I bought a larger battery and I discovered I could get it to start by cranking non-stop for about 1 minute. My suspicion was that dried any moisture inside the cap enough to get a good spark jump and cleared the flooding from all the initial cranking. That obviously wasn't ideal, and that engine had low oil pressure, so it eventually got swapped for a 5.3 Vortec. I don't know if that helps the OP any or not, but that was my experience
Interestingly, the 5.7 on my K3500 GMT400 doesn't have this issue, but I see a lot of other crank/no-starts here on these engines here. When I changed the spider injectors on my 5.7 I noted the distributor cap had a small crack (looked original too), I skeptically reinstalled it, because I was too scared to try an aftermarket one...