In post 332 in that thread, you should contact Geoff at Full-Race. He makes great manifolds and may be able to help you out.
I have used his stuff in the past.
174,000+ miles, 5/20/12 new ej257 short block, 8/20/11 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. Also CHECK YOUR OIL, these cars use it.