Thanks Gerry, i don't know if it was mounted like that on my '78, but it could.
I have two strange circles in the rust protection, i just have to find a way to make the hole coming out!!
I'll let the trombone, first because it's the original one, second because my oil temperature never get above the half! ;-)
I'll try to find this hole!!
The new one on the second picture is already in place!