I think I remember in another thread you're running Dove heads and I'm assuming intake too. If so, you might have a mis-match on the heads to intake. I'm running a Dove Tunnel Wedge intake bolted to a set of CNC'd MR Eboks. I had to have work done to Dove's intake by my local macinine shop to render it useable. It required re-cutting the intake faces. The reason I'm mentioning that is if your intake/head surface mating area is not right you would have the right conditions for an
oil sucking intake leak, hence the plug fouling.
I'd wait another 4 or 5 hundred miles and run a new compression test..