The VB became the main production version of the Mark Vs. Along with the new Merlin 45 series the B wing was fitted as standard. As production progressed changes were incorporated, some of which became standard on all later Spitfires. Production started with several Mk IBs which were converted to Mk VBs by Supermarine. Starting in early 1941 the round section exhaust stacks were changed to a "fishtail" type, marginally increasing exhaust thrust. Some late production VBs and VCs were fitted with six shorter exhaust stacks per side, similar to those of Spitfire IXs and Seafire IIIs; this was originally stipulated as applying specifically to VB(trop)s. After some initial problems with the original Mk I size oil coolers, a bigger oil cooler was fitted under the port wing; this could be recognised by a deeper housing with a circular entry. From mid-1941 alloy covered ailerons became a universal fitting.
Different propeller types were fitted, according to where the Spitfire V was built: Supermarine and Westland manufactured VBs and VCs used 10 ft 9 in (3.28 m) diameter, 3 bladed de Havilland constant speed units, with narrow metal blades, while Castle Bromwich manufactured VBs and VCs were fitted with a wide bladed Rotol constant speed propeller of either 10 ft 9 in (3.28 m) diameter, with metal blades, or (on late production Spitfires) 10 ft 3 in (3.12 m) diameter, with broader, "Jablo" (compressed wood) blades. The Rotol spinners were longer and more pointed than the de Havilland leading to a 3.5 in (8.9 cm) increase in overall length. The Rotol propellers allowed a modest speed increase over 20,000 ft (6,100 m) and an increase in the service ceiling. A large number of Spitfire VBs were fitted with "gun heater intensifier" systems on the exhaust stacks. These piped additional heated air into the gun bays. There was a short tubular intake on the front of the first stack and a narrow pipe led into the engine cowling from the rear exhaust.
The VB series were the first Spitfires able to carry a range of specially designed "slipper" drop tanks which were fitted underneath the wing centre-section. Small hooks were fitted, just forward of the inboard flaps: when the tank was released these hooks caught the trailing edge of the tank, swinging it clear of the fuselage.
With the advent of the superb Focke Wulf Fw 190 in August 1941 the Spitfire was for the first time truly outclassed, hastening the development of the "interim" Mk IX. In an effort to counter this threat, especially at lower altitudes, the VB was the first production version of the Spitfire to use "clipped" wingtips as an option, reducing the wingspan to 32 ft 2 in (9.8 m).The clipped wings increased the roll rate and airspeed at lower altitudes. Several different versions of the Merlin 45/50 family were used, including the Merlin 45M which had a smaller "cropped" supercharger impeller and boost increased to +18 lb. This engine produced 1,585 hp (1,182 kW) at 2,750 ft (838 m), increasing the L.F VB's maximum rate of climb to 4720 ft/min (21.6 m/s) at 2,000 ft (610 m).