Safety factors

It all depends on the condition of the parts.
Be very careful to check all welds and especially for any cracking or obvious wear.
If in doubt, replace anything that looks even questionable, or repair it properly.
Reinforcing and extra welding up of all of the seams would be a good idea, the factory teams did that back in the day. (Sox & Martin, Petty, Landy, Ramchargers, etc.)
My .02 cents.
Tom.