Spent a few hours on the dyno today fighting the persistent boost control issue and got it to behave (although it's still not the right way to do it). This run came out smooth but we run out of fuel up top and the clutch now slips. On this run we turned down the boost and let it rise slowly to keep it from slipping, and made 601 whp.
The car easily reached 612 whp at 5800 rpm (which is where fuel cut) and has plenty available, but I just want to keep it a little above 600 for now until the next engine (which will be built stronger) is ready, to be safe.
We're in the home stretch. Working on finding a stronger clutch (hard to do on this platform) and installing a fancy brushless fuel pump with massive capability.
Currently I have a Bully Stage 4 clutch (which everyone laughs and says they've never heard of, and also how soft my clutch petal is seems to indicate it's fairly weak on clamping). We're hoping ACT can make a clutch with a super strong pressure plate... or any other reputable manufacturer.
And then, a smooth dyno run and buttoning things up so I can finally drive it a little again.