Wow! That's a great prize for a motorsport collector! 
I would usually expect McLaren in the UK to be helpful in documenting the history of an F1 engine, for example...
"In the mid 1980s, Team McLaren dominated Grand Prix racing with their carbon fibre MP4 chassis and their Porsche-built TAG Turbo engines.
Between 1984 and 1987, TAG powered McLarens in the hands of Niki Lauda and Alain Prost captured 3 World Championships and scored 25 Grand Prix victories.
Several years ago, TMC acquired the race used parts inventory of the TAG Porsche engines from McLaren International and offered select pieces to memorabilia collectors worldwide.
Engine assemblies like this one were quick sell outs and are rarely available in the secondary market. Especially rare are those engine blocks that have a documented race history like this one.
In 1985 and 1986 Engine 42 was fitted to three Grand Prix winning McLarens driven by two of the greatest drivers in Formula One history.
The highlights of Engine 42's history are listed below:
- 1985 British Grand Prix -- Winner, Alain Prost
- 1985 Dutch Grand Prix -- Winner, Niki Lauda
- 1986 Monaco Grand Prix -- Winner, Alain Prost
- 1986 French Grand Prix -- Fourth, Keke Rosberg
- 1987 Belgian Grand Prix -- Second, Stefan Johansson
This history is authenticated by a letter from McLaren International signed by Managing Director Ron Dennis."
Motorsport-Collector_McLaren-F1-Porsche-TAG-Engine
...best of luck!
