Shane the reason I asked about the similarities between the LT1 vs LS1 Header is Speedway Motors has LS Headers cheap for the 62-67 Nova with their sub frame if it’s just a matter of changing the flanges. They are on close out for less than half price. They have 1 7/8” primary tubes , O2 bungs and good clearance for the steering shaft. They are not stainless but at this price you can modify them and have them coated. I have a set that I changed the collectors to V-band style and had coated. They only have a few pairs, I can tell you that story another day. Let’s just say I’m the reason they have them. Here’s a link.
https://www.speedwaymotors.com/G-Com...sh,205590.html
If you need any dimensions I can help.