I'm switching out to 3.8 liters and 1 3/4" headers.
This are the first generation of B&B 914-6 headers with heat exchangers. I've had them for about 20 years but they still are 100% functional and work great. These are 1 5/8".
$609.14 + shipping from 92024 or pick up in person.
Newer version of the same thing:
https://ppeporparts.com/i-30514630-porsche-...1976-914-6.html
Thanks,
Steve