Still needs more work but I couldn't take it anymore. Cracked out the Dremel and the extension. Going to gasket/port match further, seeing amor 30mm on average between all 4 ports. In the pictures you can see how some of the manifold ports are out-of-round. Only did about 3 hours of work, going for another 3 in a couple days.
Kept taking measurements in 3 different areas of the runner entries, just to make sure I'm staying to close to each port. Getting a knife edge in this manifold is difficult with the items I'm currently using. Going for a tungsten carbide single/double cut is a good idea for a Dremel.
Actually really enjoyed this first 3 hour process. Excellent learning experience.
Note to future adventurers:
Two of my runners had casting humps on ceiling and floor. These humps cause a huge squaring of the runner for me, made port matching difficult, but doable. You should be able to see it in the 3rd and 4th pictures. It took a good 20-30 minutes per runner to get the port entry within round. Cast flashing really built up on my runner from the manufacturer, so those areas needed attention. Your turbo manifold may be different, but similar. This was done using stone bits and tapered sanding drums.
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