Ted- those 4 hole plug wire holders that mount on the head, right behind the #4 exhaust port...are those a T-bird item, or where they on Non-T-Birds, too?  I don't recall seeing them on either of my other Y's but my current one has them.  

Those spark plug wire holders came as original equipment on all year Ford Y V8’s on both the cars and trucks.  Even the industrial engines had them.  I get my replacements from Mac’s and Carpenters, but they are also available from many of the other Ford and Thunderbird restoration supply houses.

Here are some links.
Eckler's Spark Plug Wire Grommet & Bracket Kit/54-64 8 Cyl Ford Thunderbird Fairlane Galaxie Ranchero Truck Full Size Ford Mercury (macsautoparts.com)

Spark Plug Wire Grommet for 1954-64 Ford Trucks and Cars | Dennis Carpenter Ford Restorations (dennis-carpenter.com) 

Spark Plug Wire Bracket for 1954-64 Ford Trucks and Cars | Dennis Carpenter Ford Restorations (dennis-carpenter.com)

Lorena, Texas (South of Waco)

While the HD truck exhaust manifold gasket with the built in heat shield is no longer available except as a NOS item, the shields that came on the cars and pickups are still available.

From the factory, the Y’s did have heat shields attached to the bottom side of the cast iron manifolds for the sole purpose of protecting the spark plug wires.  There were two on each side of the engine and fastened with the same bolts that attach the exhaust manifolds to the engine.  Whether or not they will work with headers will depend upon the header that’s being used.  They are available from some of the restoration houses.  Here’s a link.

Spark Plug Shield for 1954-64 Ford Trucks and Cars | Dennis Carpenter Ford Restorations (dennis-carpenter.com)

Lorena, Texas (South of Waco)

Thanks for the links, Ted.  I only have the square ones but they'd work great on any engine.