No they aren't unrevised heads they are B heads. Unrevised heads are tumble port C heads, Revised heads are the ones that come in 03/04 Cobras and Machs and 05 Aviators. The Mark VIII motor is a common swap in any 2V even the 99-up cars because it is almost the same motor that came in the 96-98 Cobras. No forged crank=no big deal the rods are the weak link in the motors anyway and the cast crank is more than fine. Yes it did come with the Teksid block which is pretty much the best block that ever came in a Ford. Teksid is the same company that makes blocks for Ferrarri and Ford went away from them due to manufacturing costs and started making their own blocks in house which is the WAP block. The WAP is what came in most 01 Cobras (a few got leftover Teksids IIRC) and all Mach 1s. Also comes in 02-05 Explorers and a few other applications I believe.
Anyway, if going 4V it is a good cheap way to get there and a properly tuned Mark VIII motor with a Cobra intake or even the Mark intake is a solid 300whp capable platform with the typical bolt ons/tune. The big thing you have to watch for with the B heads is they are split port intake heads and the injector only shoots fuel into one port. The other one commonly gets crudded up over time and requires a seafoam or better yet an intake pull and mechanical cleaning if possible. The other issue the B headed cars have is the IMRCs which you can rig into any Mustang with a simple window switch to activate them or just delete them and tune the car around them. It works better if they are functional until you throw boost at it, then its a good idea to delete them.
There are a ton of 4V swap threads on this very subject of a Mark VIII engine conversion in a 2V. The corral DOHC section has a pretty detailed one as do a few other places. Google is your friend as well.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.