[DeTomaso] To Drop or Not to Drop

[Daniel C Jones]

 I'm 6'5" and have installed dropped floor pans in both of my Panteras,
along with C4 Corvette seats.  A smaller diameter steering wheel, pedal
spacers (for increased leg room) and a bulkhead reduction kit round out the
modifications.  Highly recommended.  My floor pans are from Kirk Evans.  He
offers a couple of drops and mine are the deeper ones that drop the rear of
the floor around 3" and the front maybe an 1.5".  They do cut through the
crossmember but with the filler pieces, I don't think they sacrifice any
rigidity.  Jacking the car on one corner will lift it off the ground on 3
corners with no sag (doors will open and close fine) so it seems stiff.
I've not noticed any problems driving it either but I did install a chassis
stiffening kit at the same time.

As I understand it, Kirk has a revised design.  Mine's the earlier version
but here's what Kirk said about his new design:

"I totally redesigned the pans and was able to keep
 the front///bottom of the original cross-member intact
 and supply a new reinforcement which makes it stronger
 than the original---which is not that hard to do.
 I also supply new seat mount rails and my pans are
 16 gauge steel rather than 20 gauge. These pans
 fit the car far better than any this built to date."

The following comments are relative to his earlier design but may still be
of interest.  These are the big pans that cut into both the fore-and-aft
and side-to-side floor pan reinforcements.  This allows for larger seats
and permits the seats to slide fore-and-aft, unlike the drop pans that stay
within the boundaries of the original pan reinforcements.  Kirk supplies
stiffeners that run the length of the pans and also serve as the mounts for
the seat rails.  The stiffeners keep the flat pans from "oil canning".  At
the front, you cut across the floor pan fore-and-aft frame rail, cap it off
(with the shaped leading edge part of the new pan) and then weld a pair of
heavy steel u-channels (upside down) to the floor pan.  The outer u-channel
is in line with the old floor pan fore-and-aft frame rail.  It butts up
against the pan on both ends.  You weld it to the pan along both long edges
and both short edges.  It then forms a load path similar to the original
fore-and-aft frame rail.  Be sure to make triangular pieces underneath the
car so the rear rails tie into the pans.  I made filler pieces (patterned
off of cardboard templates) to close off the various gaps (there's a
sizable one around the emergency brake handle and several smaller ones both
inside the passenger compartment and underneath).  On the bottom side, I
made pieces that tie the pan directly to the fore-and-aft and side-to-side
frame rails.  Note the aft portion of the pan wasn't formed by a metal
brake.  Instead, it was a separate piece of metal tack welded to the main
pan.  Under load, that portion off the pan deflected so we welded along the
entire length and it became very rigid.  I'm pretty sure I had to trim the
metal surrounding the parking brake handle but forget the details.

Even though there is some rake built into the pans, I needed to install
stands to get the fixed headrest C4 seats in a comfortable position.

Dan Jones
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   I'm 6'5" and have installed dropped floor pans in both of my Panteras,
   along with C4 Corvette seats.A  A smaller diameter steering wheel,
   pedal spacers (for increased leg room) and a bulkhead reduction kit
   round out the modifications.A  Highly recommended.A  My floor pans are
   from Kirk Evans.A  He offers a couple of drops and mine are the deeper
   ones that drop the rear of the floor around 3" and the front maybe an
   1.5".A  They do cut through the crossmember but with the filler pieces,
   I don't think they sacrifice any rigidity.A  Jacking the car on one
   corner will lift it off the ground on 3 corners with no sag (doors will
   open and close fine) so it seems stiff.A  I've not noticed any problems
   driving it either but I did install a chassis stiffening kit at the
   same time.
   As I understand it, Kirk has a revised design.A  Mine's the earlier
   version but here's what Kirk said about his new design:
   "I totally redesigned the pans and was able to keep
   A the front///bottom of the original cross-member intact
   A and supply a new reinforcement which makes it stronger
   A than the original---which is not that hard to do.
   A I also supply new seat mount rails and my pans are
   A 16 gauge steel rather than 20 gauge. These pans
   A fit the car far better than any this built to date."
   The following comments are relative to his earlier design but may still
   be of interest.A  These are the big pans that cut into both the
   fore-and-aft and side-to-side floor pan reinforcements.A  This allows
   for larger seats and permits the seats to slide fore-and-aft, unlike
   the drop pans that stay within the boundaries of the original pan
   reinforcements.A  Kirk supplies stiffeners that run the length of the
   pans and also serve as the mounts for the seat rails.A  The stiffeners
   keep the flat pans from "oil canning".A  At the front, you cut across
   the floor pan fore-and-aft frame rail, cap it off (with the shaped
   leading edge part of the new pan) and then weld a pair of heavy steel
   u-channels (upside down) to the floor pan.A  The outer u-channel is in
   line with the old floor pan fore-and-aft frame rail.A  It butts up
   against the pan on both ends.A  You weld it to the pan along both long
   edges and both short edges.A  It then forms a load path similar to the
   original fore-and-aft frame rail.A  Be sure to make triangular pieces
   underneath the car so the rear rails tie into the pans.A  I made filler
   pieces (patterned off of cardboard templates) to close off the various
   gaps (there's a sizable one around the emergency brake handle and
   several smaller ones both inside the passenger compartment and
   underneath).A  On the bottom side, I made pieces that tie the pan
   directly to the fore-and-aft and side-to-side frame rails.A  Note the
   aft portion of the pan wasn't formed by a metal brake.A  Instead, it
   was a separate piece of metal tack welded to the main pan.A  Under
   load, that portion off the pan deflected so we welded along the entire
   length and it became very rigid.A  I'm pretty sure I had to trim the
   metal surrounding the parking brake handle but forget the details.
   Even though there is some rake built into the pans, I needed to install
   stands to get the fixed headrest C4 seats in a comfortable position.
   Dan Jones