Well I would recommend forging the bottom end.
If you plan on running a turbo on a SOHC for street use-expect to run a low amount of boost. 5-8lbs. Turbos on the SOHC is still an exotic setup so there are a only few folks that can quote what they've done.
Because turbo charging a SOHC Mustang is kinda rare expect to pay more than your standard Supercharger kit and installation.
A Boost controller should be included in the kit, if not, get it!
Bottomline: Get smart on all the requirements because the cost is serious.
1. Forged Bottom end
2. A Lot of $$$$$$$$$$
3. Knowledge on what it will require/changes
Example:
the Mach 1 DOHC
Induction Concepts
390rwhp @ 4psi
511rwhp @ 8psi
Related links:
TurboCharged Power
Turbo Mustangs
Induction Concepts
Pro Turbo Kits
There are couple notable cars runing single and twin tubo set ups.