I started a thread a while back on the D627 pipes, the original design is actually from the T Bolt car in the 60s. I think even non Ford guys know a little about this story. The headers are direct copy's. I will look to see if I can locate the first thread as there was a lot of input from everyone, even some that were running them on their car. And some other interesting setups for mustangs as I recall. Lots of info there.