Agree with the previous posts...
In addition, buy grade at least grade 5 (preferably grade 8) bolts. Depending on whether you have intake and heads installed, you will have 500+lbs on that stand. Do not trust that to hardware store soft (grade 2 or less) bolts.
This is a big fast forward, but - I personally would never try torquing heads on an engine stand. I've never tried a modern Hemi with AL heads. I have tried the older cast SB and BB heads on 60's, and 70's vehicles. You can't get a good torque with the springiness of the engine stand while it's chasing you around the shop. Torque them to a low/equal value on the stand and then finish in the vehicle.