HRG Derrington Headed MGA Discovered - by Stuart Mumby

Photo for HRG Derrington Headed MGA Discovered - by Stuart Mumby

Serendipity. Every once in a while a happy discovery is made, just by chance. Irene and I were strolling along the riverside path in the historic city of York recently and we passed a large house, one that we have walked by many times and mounted on the roof of which is a weather vane (wind direction indicator) in the shape of an MGA.

Each time we have walked by I have said that one day I will knock on the door and ask the owners if they actually have an MGA. Well, this time I did, announcing myself as the Chairman of the MGA Register.

The gentleman of the house did, indeed have an MGA, or rather his wife did. And what's more he would open up his garage for us to see. What he revealed was no ordinary MGA. The car, a 1600 Mk2 Roadster, has been in his wife's ownership since 1982. In 1979 it was fitted with a genuine HRG Derrington cross-flow head and twin webers. The owner allowed me to take some pictures of the installation and these are reproduced with this article. As can be seen, the inlet manifolds have the Derrington name cast into them and the valve cover has the HRG Engineering name-plate attached. The car is also fitted with a close-ratio gearbox. It is very rare to see a Derrington equipped road going MGA in the UK, though the firm of Brown & Gammons were marketing a similar reproduction item and Moss sell a cross-flow head of their own design. A brief Google search shows a healthy interest in the original Derrington heads in the USA.

 My first MGA was a standard 1600 Roadster which I sold in 1998 to fulfil the dream of owning a Morgan. Unfortunately, though the car was a beautiful specimen we could not get along together. When I later visited the new owner of my original MGA he had fitted an genuine Derrington head which he had acquired from a friend in the trade.

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Reader Comments (2)

Picture of alan herrod
alan herrod (Australia)
on January 3, 2013 11:15pm
I have owned many MGA cars of all the usual types. I liked them for their simplicity but always regarded the engine as a chugger compared to other more sophisticated units. I then bought a TVR Grantura with a 1600cc MGA unit and a Derrington crossflow head with Webers......sensational is the only way to describe the transformation. I never drove an MGA with this set up but I would imagine that it would utterly transform the car. Does anybody know how much the power uplift is? Also it revved much more freely.....not a chugger then!!!
Picture of Clifford L Morgan
Clifford L Morgan (Colton, CA)
on January 26, 2013 3:26pm
I have a 1960 MGA with an MGB engine with a Moss mx cross flow head that is very similar to the derrington head I am told and I am very pleased with it. The increase in power just from the head is represented by Moss as 25 percent. I believe it because you can really feel the extra power. What a difference. I am running 1 and 3/4 inch SU's. I have nothing but good things to say about this setup. I also have a fast street cam and header. I drive this car every day and have had this set up for over 5 years.

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Last updated on November 27, 2016.