For a set of well-tuned, equal length headers, look at a big block Ford GT. But to use them, you'd have to have a rear engine, or run them through the firewall and along the trans/diveshaft tunnel to get them out the back. And drive from the back seat.
KS
For that matter "all" Ford GT's had 180* headers.
Yup, I'm aware of that, but although the FE and small-block iterations are similar, they're not exact duplicates, and since both this site and this thread seem to be about FE engines, I narrowed my reply down just a 'scosh'.
KS