If you don't raise the rev limit, then the powerband is much smaller then that of a GTX28 based turbocharger. If the limiter is raised, then youd get the same useable powerband in terms of RPMs. However response (foot hard down to getting boost) even when within the prime rpm band will still be slower making a car feel laggy...
The second issue is the fact that Azz doesn't/didn't know what the in-depth spec of the engine was, as its TMD's old engine and of course Dave Burwash is no longer with us... Pointless pushing an engine when you do not know what the tolerances/measurments/true spec of it is... Which may be partly the reason why it lifted the head off the block at big boost...
This wants a Headstud Conversion. Known, stiffer valve springs and a higher limit. Then it will live up to the "Monster" in the title in my opinion!
But hey, all in good time dude! Get it ready and driveable, worry about it over winter when your not using it! Then turn it up!
Glad to see you've got it back, make it yours again, clean her up then when you've enjoyed it a bit, take it back!
PS, those wheels look wide!