Data and facts about

the GTP-13

the historic Ford P68 F3L


GTP-13: Vacuum moded Kevlar-honeycomb reinforced GFRP, Epoxy matrix. Sealed cockpit. Total body mass (w/o windows and w/o paint): 24kg (weighted).

P68: Aluminium body made from 0.030" (approx. 0.8mm) thick* Aluminium sheet metal. Unsealed cockpit subjected to rain. Total body mass (w/o windows and w/o paint): approx. 38kg**.


GTP-13: Aluminium and steel sheet metal based monocoque design. Two-piece rear bulkhead allows for easy installation and removal of the drivetrain. TIG-welded, painted and waxed steel members, solid and Cherry-Max riveted aluminium members. Total mass: 91kg (weighted), torsional stiffness: 12kNm/° (FEM-computed with discretized rivet connections, stiffening roof structure influence not considered in computation).

P68: Aluminium and steel sheet metal based monocoque design. Single-piece rear bulkhead requires separation of engine and gearbox for installation and removal of the drivetrain. Oxy-Acetylene welded steel members, Pop riveted Aluminium members. Total mass: ?, torsional stiffness: ? (at a rough estimate a fifth of the GTP-13's torsional stiffness***).


GTP-13: Ford Windsor V8-SB Dart Aluminium block. Dart Pro 1 Aluminium cylinder heads. Displacement: 5957cm³ (364in³), naturally aspirated, petrol fueled. Mechanical power outpout approximately 600hp (note: not measured). External electric coolant pump, temperature controlled. Dry sump oil system, dual filtered, dual oil tanks. Electronically controlled wasted-spark ignition. Electronically controlled port injection fuel system, lambda-control loop, slide throttle arrangement. Dual catalytic converters, dual reflexion-type mufflers.

P68: Ford Cosworth DFV. Dry sump oil system, mechanical port injection fuel system, slide throttle arrangement. Exhaust system w/o catalytic converter and w/o muffler.


GTP-13: Quaife ZFQ five speed (5+1R), synchro mesh.

Cardan shaft shifting mechanism.

P68: Hewland DG300 five-speed gearbox, unsynchronized. Cardan shaft shifting mechanism.


GTP-13: Independent front and rear, rear wheel drive. Infinitely variable stabilizer bars front and rear. Dual adjustable shock absorbers front and rear.

Wheels: Ø15", w=14" rear; Ø15", w=10" front.

P68: Independent front and rear, rear wheel drive.
Wheels: Ø15", w=10-11" rear; Ø15", w=8.5-9" front.


GTP-13: Greatest length: 4.450m

Greatest width: 1.855m

Roof height: 0.960m (37.8") (w. 0.110m ground clearance)

Total mass: 740kg (w. oil, w. coolant, w. 50Ah/1kA battery, w. radiator fans, w. catalytic converters, w. mufflers, w. A/C system, w/o fuel, w/o driver)

P68: Total mass: 1480lbs* ≅ 671kg (The Ford P68 did not possess radiator fans, catalytic converters, nor mufflers, naturally it did not have an A/C system and furthermore had installed narrower tyres and wheels than the GTP-13).

*   ...Autosport Magazine, March 22nd, 1968, p6-7; Article by Bolster, J.

** ...Computed from body surface area and wall thickness.

***...Estimation is based on the measured torsional stiffness of the Ford P68 sister car, the "Ford Honker". The latter was designed

       at the same time by the same designer, Len Bailey.