i'm putting together a new motor for my '81 and its going to be putting out about 50 extra horse. will the factory clutch hold up, or should I upgrade?

 

Im in the process of building a new motor myself and Im just installing a new clutch from auto zone no need for any thing more unless its a high out put motor 50hp shouldnt need a different clutch

 

I would only say that if you've got the motor out anyways, unless the clutch is pretty darn new to begin with, there's no reason not to replace it. If it's got some miles on it, it kind of makes sense to replace it while you have things apart. Pulling the motor or tranny is kind of a big job. There are better clutches out there (like Marlin Crawler) that would be an upgrade, and they're aren't very expensive, but no, there's not really a need to upgrade.