Well i think for that price you might be able to get something from DSS or CHP (maybe just a teeny bit more) so that all depends on what you want. I personally like OEM quality...i've seen a lot of aftermarket engines go out quick whereas i've seen a lot of OEM engines take a beating and keep on rockin. But, for the money spent you can probably have a better engine than what you'll get with the Cobra engine, since essentially all you're buying is a stock 302 with GT40P heads and a crappy cam in it which you would be better off swapping out anyways.
There's a couple ways you could look at this...you could get Thumper heads for what, $600 or so? I'm pretty sure they'll out perform P heads so if you have a 302 already you can swap them on and even with a stock 302 cam (not the Cobra cam) you'll probably be making more power than a Cobra engine does, even with its 1.7 rockers. Get a cam and intake and you'll be way better off than the Cobra engine.
Or, spend that money on a 347 short block and throw on some E7s. Yeah, there's gonna be some on here who say that's retarded, but 42 extra cubes is 42 extra cubes, not to mention the added compression you'll probably get. Obviously the E7s aren't the ideal head for a stroker and they WILL choke it, but it'll still scream and make tons more power than a stock 302 and then down the road you can get better heads when the funds are there.