We've tried again to re-fit the intake manifold, but it's leaking again. I've put a couple of photos below. We think there are two problems: 1) we ordered a Mercruiser Vortec gasket (for a Chevy small block), but this has pure rectangular ports (see the 2nd photo below), the water ports on the Indmar intake have an extra cut out (you can see the imprint of the correct gasket on photo #2); and 2) we had to fill our intake as it wasn't flush, but the filler seems to have not set with a flat surface (even though it was rated for engines).
Can anyone offer any tips on how to repair intake manifolds? It looks like the previous owner hadn't flushed through the intake properly, hence the corrosion.
I guess one good thing, I'm becoming an expert at setting the timing up!
'92 190 Prostar 260hp Indmar.