From HCVC onetrack 14-12-2011
The 3.38 model number stands for 3 ton capacity and 138" wheelbase.
This is the "redesigned" BMC truck released in 1965 in 2, 3, 4, & 5 ton capacities, with 3 wheelbases.
The "new, improved" design featured a one piece windscreen, larger rear corner windows, dual headlights, redesigned (shortened) doors that incorporate a step, and a new central instrument panel with padded dash.
The 2 & 3 tonners only had one engine option, the 4 litre petrol engine, rated at 90 BHP at 3000 RPM, and producing 203 ft-lbs of torque at 1000 RPM.
There was a 5.1L BMC diesel option available in the bigger 4 & 5 tonners.
The petrol engine ran a leisurely 6.4:1 compression ratio, the truck is on 8 stud 7.50 x 20 tyres, and the rear axle ratio for the petrol engine is 7.2:1.
These trucks were quite good, under-rated lorries, and they did not sell in the numbers they should have. These trucks were the product of a BMC Corporation that was still functioning properly .. before the British idiocy of the late 1960's and 1970's that saw massive U.K. Govt political interference, gross mismanagement, destructive bloody-minded unions, and the industrial destruction created by the lengthy coal miners strike of 1974 .. that finally sent British vehicle manufacturing industry into unrecoverable decay .. where massive losses eventually destroyed most of what had been built up over the preceding 70 or 80 years.
Hope this helps,Pete
if there is a austin fanatic anywhere who could help me that would be great 
