Is it safe to use the driveshaft from a slant 6 904, on a v8 360 904?

Want to build a loop, start here....

http://www.speedymetals.com/c-8241-round-pipe.aspx

You can build something like this if you have connectors.

there seems to be some demand and margin here for a guy who can fab steel ,hmmm I wonder if I know anyone who doe's that on the side ?