Dropping a Spitfire tub onto a GT6 can be easy, if you have a full plan for the following differences between the two bodies:

1) The Spitfire body uses an upright gas tank behind the drivers seats and in front of the trunk. A Spitfire gas tank will have to be obtained along with the body, as well as feed lines, for use on the GT6. The GT6 gas tank is mounted below the rear hatchback area, and will not mount in a Spitfire tub.

2) If the GT6 you are using uses the Rotoflex rear suspension design, the shock mount locations are in the fenderwells on the GT6 body and NOT on the chassis as in a Spitfire. Shock mounts will have to be added to the Spitfire body for use of a Rotoflex rear suspension. Fortunately, the fenderwells of the Spitfire and GT6 tubs are the same sheetmetal, and small guide bumps are present to help align the sheetmetal of the shock mount for spotwelding. This makes it easy to simply cut the shock mounts out of an old GT6 body and weld them in place on the Spitfire fenderwells. Or fabricate your own mounts and weld them in place.

3) A GT6 with Rotoflex uses a different location for the rear suspension control arms. Once again the sheetmetal of the bodies is similar and the mount locations and holes for the GT6 control-arm bolt are present on the Spitfire body. (Look on the lower vertical wall behind the seats in your Spitfire or GT6 and you will see two rubber plugs covering the unused holes there.) Front control-arm mounts must be obtained and installed (welded) into the Spitfire tub. You could cut the welds loose on the control-arm mount currently on the Spitfire body and move it over to the correct location (hard) or you can obtain another set of mounts and weld them place. (Best source for these pieces are off of an old Spitfire or GT6 tub, but they can be purchased separately from Victoria British P/N: 11-670) The GT6 position is toward the center of the car about 5 inches, and will not interfere with the current Spitfire mounts. (There is no need to remove the spit mounts to fit the new ones in place for the Rotoflex rear suspension.)

Note: control-arm mounts as individual pieces ARE available from Victoria British.

4) A GT6 with Rotoflex has the cable guides for the parking brake moved off of the chassis for clearance reasons and mounted to the GT6 body. Using a Spitfire tub will require that you add cable guides to the Spitfire tub as well as shock mounts. Once again, the easiest way is to cut the necessary pieces out of an old GT6 body and weld them onto the spit tub, but without that, suitable guides may either be fabricated or the guides can be cut off a Spitfire frame, inverted, and welded onto the Spitfire tub.

If your conversion is NOT using a GT6 with Rotoflex, things are slightly simpler, (accept for the difficulty of obtaining and modifying a non-rotoflex GT6, quite rare here in USA!)

One more intriguing idea is to use only the Upper Deck of a Spitfire MK I, MK II or MKIII body and any GT6 up to a GT6+. The idea is to simply take the "lid" off the GT6 and install the Spitfire trunklid in its place. As seen in the above steps 1-4, swapping a Spitfire tub onto a GT6 will require some structural welding to Spitfire tub, but a different approach can be taken if you are only able to use a handheld spotwelder and are interested in having a spit-6 with greater trunk space.... The early body-style Spitfire used a bolt-in windshield frame, with a bolt-on removable hardtop. When the early GT6's were made, they simply used the same scheme, and the front of the GT6 top was still simply bolted to the top of the windshield frame. The rest of the roof is brought down into a fastback and spotwelded to the tops of the fenders of course, at the rear fender top seam as seen on all spitfires and GT6's, and then finish welded horizontally across the back above the license plate area. The spotwelds on the fender top can be drilled out, the front can be unbolted, and the area across the back above the license plate can be cut leaving a large flange for use with the Spitfire body. The Spitfire rear deck and trunk area will fit right where the GT6 upper was, and can be spotwelded in place across the tops of the fenders as the factory did, with these spotwelds being hidden by the fender trim piece. The rear area above the license plate could possibly be finished with simple spotwelding as well (No major welding required), then smoothed with filler for a clean finish. The gastank filler would have to be moved.... either down or to the driverside fender, alas.. This would truly be a "ragtop GT6" rather than a "spit-6". Additional bracing should be added to the area behind the seats where the Spitfire usually holds its gastank, to avoid the inner area between the wheelwells from parallelogramming. A square frame made from 1-inch square steel tubing could be made, to make the same structural rigidity that the Spitfire gastank provides, or a simple flat sheet could be installed. I'm sure some scheme could be made to allow the trunk to extend into the area behind the seats..... I have not tried this, and may never do so! But if anyone does, I'd like to see the final pictures.