R/R piston rings from underneath?

[Hozer 88GTConv]

Okay, I've checked everything else and it has to be a cracked oil ring on number 5.

I recently rebuilt the heads and would prefer to snatch the motor out and pull the pan and r/r the rings on number 5 leaving the top end intact. Really don't want to pull the heads again (gaskets, head studs, etc).

Can I r and r number 5's rings from underneath on an engine stand?

I have never done a ring job and realize that I may have to take it apart anyway and hone it if the rings are really messed up. But it is holding 175 PSI on a compression check and not losing any pressure even after an hour of sitting. So, I think it has to be a cracked oil ring...
I have r/r'd valve seals twice and r/r'd the intake manifold gasket 5 times to make sure it isn't pulling from the lifter valley.
It is only doing this on number 5 and it is pissing me off.
It also NEVER smokes. All other plugs are perfect.

I just need number 5, it's burning a quart every 150 miles and fouling the plug royally. Plus it's killing my idle, f-ing up the octane, and I'm anal.

Thanks in advance...maybe I should just stroke it and be done with it...

By the way, road trip from New Smyrna Beach yesterday I averaged 3900 RPM with 3.73's on my T-5 in 5th. The needle was buried so I have no idea have fast I was going. If the needle is calibrated past 85, I had to be averaging 105-110 for the better part of an hour.