Supersonic indeed!
Now for the questions?
What car is they on ( 69 Gtx or 68 runner ) and why SO BIG?
If an exhaust valve is approx. 1.81 diameter in a good wedge motor then 2.00 ‘OD’ pipe should be plenty?
Maybe 1-7/8 od is ok too in most cases, or am I missing something???
Would this design work my 71 Gtx (512, 440-1) and how much for another set ( please ) lol...
563 CID and 440-1 CNC 345 heads, I don't know the specifics of the build but that foundation can easily make well over 800 horse. Regardless of the valve size his headers are not too big.
As far as 1-7/8" headers, I don't think I'd run them on anything more than a warmed 383
