Slack in new timing chain

FWIW-
I have a particular brand of TC that I use on a regular basis. Last time I ordered one for SBM it had too much slack in it. Problem was the root diameter of the teeth was cut .012" smaller than it should have been, causing the slack. Ended up using a Cloyes.
Like stated before, use the tensioner. The great thing about SBM's is the crank/cam CL, the downside is the longer chain builds slack quickly with use.