I agree with Other Eric. I would remove the overlying stuff to get full access and use a high quality Vice Grip that won't slip off.
And then I'll add, admittedly because I can't stand someone else getting to it first: Lubricate well, grab the shaft firmly, and gently work it back and forth till it pops
The manifold is off a Mk2 Golf?
It's hard for me to know exactly what these things cost me. I'm guessing a LOT, but I like them, so that's that.
It's gonna be a 1.6, with the Heron head, 80.5 bore x 77.4mm stroke based on the crank I'm using.