In the channel on the lid . I ended up not using one on mine just figured it would hold water and start to eat away at the paint Posted using the Full Custom H.A.M.B. App!
Hemi and Deathrow are probably confusing the OP. From Ford there is no seal. But any hot rodder can put a seal where ever he wants. If it works is yet to be seen.
On a runble lid, pack everything in waterproof cotainers. With a trunk, you can extend the troughs in the quarters so the water goes to the panel where the lid latches. You put drain hoses in the panel.
On my coupe we put rubber ****ons to cushion the decklid, but did not put a seal in it. After 4500 miles...some thru torrential downpours...there wasn't any problems.
On all the deuce roadsters and coupes I've completed we seal the ends of the rear drip pan to the side drain troughs and put drain tubes down thru the floor, problem solved. Been in lots of rain storms and the trunk stays dry and clean. Never have put any kind of rubber seal in the channel or on the lid.
Stuff stay pretty much dry. We just cover luggage in a plastic sheet to be sure. No seals. Though we have no interior except the seat occasionally I feel we get a slight whiff of exhaust fumes through the lower rumble lid to lower panel gap, it's just the way the lid swings and it needs the bigger gap to clear on its arc.