hey joe, even modern cars with emission systems, do not get fire to the ignition coils until the ignition computer has seen at least 1 full revolution (#1 cylinder tdc 2 times on the crank shaft sensor). on units with GM HEI, this helps prevent a "roll back" where the ignition spark from the key moving between run and start causes the ignition of any combustible material in what ever cylinder was close to TDC on the compression stroke when the engine stopped last, and because that cylinder has not yet hit TDC, the engine rolls in the wrong direction, just as the the starter bendix hits. this is why some 4.3 GMs (among others) have a starter bracket that mounts to the back of the starter.
But.... that 2 revolutions happen so quick there is no way -that- adds to any cranking time that anyone should be able to notice, unless you were looking for spark from the coil wire.
have you taken vacuum measurements?
have you measured engine crank speed?