1969 Race Dart w/ 426 Hemi- garaged for 45+ years

If it were me I would want sooo bad to fire it up before I pulled for teardown.
I think you speak for us all. But IMO the risk is not worth the reward. That engine could be minty fresh and perfect inside except for a rust ring and I wouldn’t want to try and find one matching piston. Let alone the impossibility of finding one if they’re custom. A broken ring land could set it back a long long way. If it were a 360 that sat 40 years I’d be pouring gas down its throat in the first 10 minutes. But a day 2 426 hemi garners a little more respect and care.