the stock driver shaft will handle the power, but the stock U joints are suspect. also the stock drive shaft is rather heavy, and will have some balance issues at higher rpms. over all the best thing you can do is order up a new shaft with larger U joints from a place like inland driveline.
Following what the other poster said, you might look at aluminum Aerostar (i think thats what some people here used) driveshafts. They can be found cheap and are both strong enough for your app and lighter than stock driveshafts.
NOOOO, ditch it.9.0-1 302, AFR 185's, and 125 broke it on the dyno. Not even from shocking it at the track. On the dyno at about 125. Twisted it into two. The thing had cardboard inside, and was extremely thin. Took out a lot of good parts when it went.
The guy who bought my old 427 Stang (67 fb) managed to break the Toploader 4 speed behind it, plus the 9 inch rear (28 spline with 2.50's) The driveshaft came thru unscathed. If it ain't broke, don't fix it.
I generally agree with that, and probably even for this scenario if it hadn't happened to me.It took out my entire exhaust,cracked my bell housing, stall touched the back of my block and tore out two studs, broke the tranny pump and tail shaft. I was able to fix everything but the converter and it still cost me 750 to fix it, not including my exhaust.