thanks. it was built by a company called DC&O, not sure if they still do, but they used to do a bit of v8 supercar stuff. tb's are 50mm in diameter.
there are many more options out there now. I bought it probably 5 years ago, back then, the only other options I knew of was the harrop hurricane for the 241 heads.
nothing wrong with the manifold, only the finish that I'm not 100% happy with, but to have my time again I'd probably opt for a Shaun's 8tb setup, it's a complete billet item, has the vacuum chambers in the flanges, get the injectors moved to underneath, would be a sweet looking bit of gear, but when they start at $8,000 for bare manifold only, makes for an exercise you've really got to love to justify it