Our inveterate, lexically entertaining Q may be on a brief but culinarily rewarding sojuourn al la Francaise... Q travels, from time to time, to France to stuff himself silly with locally unique cuisine and wine... and, perhaps rechauffe.. waiting for a report on his latest adventure. In the mean time, using Q's favorite resouce; O.E.D., I find the following to support jno's offering:
"
Dead...Used from 16c. in adj. sense of "utter, absolute, quite." Dead heat is from 1796..." Therefore an interpolation would mean a race of any kind resulitng in a neck and neck or photo finish, an "utter, absolute, tie"...