MGB production jumped for 1971 as some radical new colors were introduced. This was the first year that roadsters and GTs shared the same colors. Engine changes included new pistons with three rings instead of four and press-fit wrist pins instead of a fully floating design. A new standardized folding convertible top replaced both options previously available. Wire wheels were discontinued in the U.S. in June 1971 and only the Rostyle steel mag-style wheels were available.

The 250,000th MGB was built in June 1971 and it was a U.S. specification GT. Roadster production rose 20 percent, from 20,072 for 1970 to 24,031. Of those 24,031 roadsters sold, fully 75 percent (18,994) were sent to the U.S. Meanwhile, 3332 roadsters were sold in the UK, still with the much better Mk I dashboard without its safety pillow and with a glovebox.

MGB GT sales also increased, from 11,380 to 13,612 but again more evenly divided between the U.S. and UK. American sales totaled 6890, while UK buyers purchased 5558 of the useful Pininfarina-designed hatchback. Base price for the 1971 MGB roadster was now $3140 in the U.S. and the MGB GT started at $3495.

The 1971 color palette brightened pleasantly. Apart from the special order Black, (rarely seen in the U.S.) other tones included Bedouin Beige, Midnight Blue, Teal Blue, New Racing Green, Mallard Green (at the end of the model year), Mustard, Blaze Orange, Flame Red, Bronze Yellow and Glacier White. Interiors were Black, Bedouin Beige, Teal Blue, New Racing Green and Green Mallard.

Significant changes were afoot for 1972, which would see the return of a glove box, fresh air vents and a redesigned heater, a center console, and a change to brushed nylon center panels in MGB GT seats, which proved disappointingly short-lived. The black interior would be replaced with Navy Blue, which lasted until mid-1973.