So, I ordered a new pump. I finally got around to working on the pump, and just happen to glance at the old one, and the part number writ upon it.
The new one is on the left. Notice anything fishy?

That's right, the idiot at Advance gave me a M-65C instead of M-65 B!! It's 5/16" longer, so the pickup is too close to the pan, thus starving the engine when it tries to pump at more than 50 rpm.
Moral of the story, double-check your part numbers before you put it on.
And if anybody needs an oil pump for an Argentine motor, 20 bucks and it's yours. Only used for a couple hundred miles.
The new one is on the left. Notice anything fishy?

That's right, the idiot at Advance gave me a M-65C instead of M-65 B!! It's 5/16" longer, so the pickup is too close to the pan, thus starving the engine when it tries to pump at more than 50 rpm.
Moral of the story, double-check your part numbers before you put it on.
And if anybody needs an oil pump for an Argentine motor, 20 bucks and it's yours. Only used for a couple hundred miles.