My 300H had a very thick insulation pad made from
some sort of fiberglass, or asbestos wool in an heavy aluminum foil envelope
under the intake manifold and extending outthe back. It seemed to me to be
factory made, but can't be sure. I've always wondered what had happened to cause
the manifold heat valve to be removed, the choke to be converted to manual, and
I had assumed that pad was all part of it.
When I got the car, my neighbor, who was an older mechanic and who
was knowledgeable, commented that I should just use the choke to get it started
and get it off choke as soon. Big engones, he said, don't need much choke once
running (?).
My drivers side seat was raised up wooden blocks under each corner. The
original owners was a Navy fighter pilot (F4H) who was killed in 1966, and I got
it from his family.