[Healeys] Engine oil

[Jaap Aeckerlin]

Friends,
I've been trying to follow the conversation on engine oil but I have to
admit I got lost - too many technical words I do not know.
When I picked up my completely rebuilt BJ8 engine from the machining shop
(and they know what they are doing, my engine was the 26th Healey engine
they rebuilt that year) I asked them what oil I should use. To my surprise
the answer was "use the 15 W 40 from Gamma". Gamma is one of the largest
do-it-yourself chains in The Netherlands and their oils are about the
cheapest oils one can get. The label on the can states  "API  SJ/CG-4" (and
also ACEA: A2, B3, E2 but as ACEA is a European group I don't think that
will say much).
Is there anyone out there who can tell me what this API indication means,
and how much risk I run using this oil?  Have only run about 1,000 miles and
just changed oil plus oil filter. (For the gearbox/overdrive I use Penrite
oil).
Thanks
Jack Aeckerlin, The Netherlands
1964 BJ8 29432