What oil?

Thanks, jefflock and longgone.
When I bought the car in May'07, the previous owner had just
changed oil...said he used Valvoline 10-40.
Car seems to be running fine, but I want to change oil before
taking out of storage.
If these ZDD claims are true, I want to use the correct oil/additive to match
as closely as possible the oil that the motor required in '68
(so not to damge lifters, etc.)
Could you guys check out the site http://www.zddplus.com/index.htm
and help me decide what to do.
Seems like "modern" oil is not what I should use?

Thanks, Rick