Even as early as January of 1975, when the TR7 was first launched in the U.S., the 16 valve engine (called a 4 valve engine by BL) Sprint version was expected to follow fairly soon after. This was hardly surprising, since the TR7 already used the Dolomite sprint bottom end mated to the 1850 head. Yet the TR7 Sprint was never launched on either the European or U.S. market.
A small number of pre-production TR7 Sprints were in fact manufactured between February and October 1977, but full production was apparently killed off by the strike at Speke during '77 and '78. Estimates of the size of this run vary. 25 is the most commonly quoted figure, but accordingly to the Archivist at the British Motor Industry Heritage Trust, the total number of cars manufacture was approximately 60 all with chassis numbers prefixed with letters ACH and engine numbers prefixed with CH and suffixed with HE.
There appear to have been two main batches of cars, one of 25 and one of approximately 35 with one or two cars manufactured outside these batches. These cars were all built using the TR7/8 bodies of the day (actually the '78 model) and were Fixed Head Cars with the interior lights on the doors. The cars were fitted with the same brakes as the TR8 being produced at the time which used larger pads than the TR7 ones, but are still only 2 pot callipers.
Of the first batch, the majority seem to have been Left Hand Drive cars exported to Europe and perhaps some went to the U.S., though since they did not have the emission control systems this would seem unlikely.
The first 4 cars were apparently not properly documented and so details of these are difficult to obtain. ACH1F is presumed to be the first of these cars and this is a RHD car.