modularfords.com is your friend, as is svtperformance.com
these things can handle 600rwhp all day long, and be dead reliable. i've had the bigger blower on my car for almost 3 years with zero issues--zero. i have the stock tranny, stock clutch, and virtually stock rearend--just springs, an IRS brace, and subframes. honestly can't believe that the stock clutch has lived at nearly 600rwhp for almost 3 years.
if you want to be serious about launching at the strip, then you'll need to upgrade the IRS, or go solid rear. you'll also have to add an aftermarket clutch, and tranny input shaft. but the bottom end is strong enough to let you go deep into the 10's