Your 1979 MGB was supplied with a Stromberg carburetor which has an automatic choke. If this is still the carburetion on the engine, chances are there is a problem with the choke – or – more easily, there is a hole in the rubber diaphragm around the air piston in the carb.
The compression should be, first of all, consistent within ten percent. Figures from about 110 to 180 are OK – as long as they’re all within 10%. The number three cylinder (third from the front) is always the problem cylinder.
The firing order is 1-3-4-2 anti-clockwise (counterclockwise). Conventionally, the number one spark plug wire exits the distributor cap at 1:00 – 2:00.
Hope this little bit helps!
I do have some videos on YouTube that might be of some assistance you to. Find them by searching for <universitymotorsltd>
John Twist