[Hammer]

Well, first thing I would do is pay less for the blower....

If you're looking for 490 HP at the flywheel, it can be had quite easily.

My Procharger w/intercooler cost me about 2/3 the price (4k), and my modified GT puts out around 450 HP (flywheel) with a safe 8lb. pulley.

Next up is to look at your IRS rear. I don't think its gonna take that sort of power very well. So some changes may be in order for the rear... I would get in touch with e reputable shop and see what they suggest.

Also, do Cobras have sub-frame connectors? If not, you'll want to get some considering the amount of power going through the chassis.

And most Important: your fuel system, ignition, and tune...

The safety of your engine depends on it...
You may have to go to larger injectors, a larger fuel or add-on pump, and maybe even a new MAF calibrated for the new injectors.
The stock ignition may or may not live well with the forced induction, and it may well depend upon how much boost you decide on going with.
Finally, a custom programmed chip is a MUST for a daily driver forced induction modular. The safety and the power all come from the tune.

My recommendation is to do it right, don't go cheap, and get a nice, safe, custom tune on a dyno from a reputable shop.

Sure you can strap on a blower for cheap and put the 10-12 lb pulley on it and get some nasty HP out of it. But you'll be slower than a bicycle if you blow your engine or IRS.

Be safe out there...