I have a glenwood Jet boat motor plate for a B/RB or Hemi and the four holes that are tapped (1/2 NPT pipe thread) are off to the water cast holes in the block. I'm planning on enlarging them to 3/4 NPT and I was wondering if anyone knows of a drawing or the correct location for these cast locations?

Thanks Brian

The Mopar Performance engine book has the dimensions in it.

I'd wait until you get your block then paint around the current holes w dykem, bolt it up for a pattern then cut them ,that way they will be dead on especially since a mtr plate is more likely to leak this just increases your odds.

That looks like a v-drive plate. You can use a water pump gasket as a templet.You better mock-up a block with the plates and see the angle of the engine, the exhaust logs, pump alignment,ect.