Stock Driveshaft Strength

[201fireman]

How much HP will a stock SBC driveshaft handle?  It looks like about a 3.5" shaft that necks down to 2.75" near the ends.

[714024SPEED]

When it falls out you made 1 hp to much lol just kidding .with a good solid u joint I have had cars making 500+hp. Usually the u joint is the weak link.

[Blackhawk]

Typically the driveshaft is limited by RPM more than anything.  With a non-overdrive transmission you usually won't have an issue, but if you have a manual transmission or newer overdrive automatic it's not a bad idea to figure out what your driveshaft RPM will be and size accordingly.

Make sure you're using non-greasable U-joints, they're much stronger than crossdrilled U-joints.

[201fireman]

Thanks folks. 

[Blackhawk]

I'd have to check to be sure, but I want to say I ended up with a 3.5" steel driveshaft balanced above 10,000 RPM.  With how long our driveshafts are the critical speed (where it starts whipping and trying to go through the floor) is pretty low.