Dang! You get quick replies here!!

Thunderbucket,
Yes this thing came out of a truck and is going into
an El Camino with an auto tranny, so it has only
a ring gear on it.

We only want to run it for about 30 seconds,
to time it and make sure it has no "We have to pull
it back out again!!?!?!" issues. So no cooling.
We used to run similiar engines 440magnums etc
on engine stands in o'l auto shop for about three minutes
regularly without noting any thermal problems.

There will be 4 guys.... But we will also hook it to
a heavy duty ceiling hoist so it can't fall over if
some goes awry.

Thanks for the rev tip that would be easy to over look
and.... well nevermind

Many thanks Thunderbucket