If you're getting ready to paint an engine in "MG Maroon" as on early MGB, I highly recommend Duplicolor Dark Canyon Red Paint. It can be found at Napa Auto Parts stores.

This paint is a dead-on color match for MGB and many other B-Series engines. Not only is the color as close as you will find, but this stuff is very durable. It is not affected by coolant or many other chemicals like other paints I have used. I used a competitor's paint advertised specifically as MG engine paint. It streaked and stained the first time coolant and oil touched it! On another car I have this Duplicolor paint and it still looks great after 25 years.

Duplicolor Dark Canyon Red Paint: Manufacturer # EDSSM288