2 headers companies come to mind. TTI - Stepped headers @ 1-5/8 - 1-3/4 Hooker Super Comps @ 1-3/4 I have two sets of the Hooker Super Comps and have ZERO complaints about them and there performance. Fit was perfect unless you have a Lakewood scatter shield, but is also an issue with the TTI headers. On my A body, I had minor clearance issue with the TTI header. On my ‘73-4 spd 360 Cuda & my ‘79 360 Magnum, the Hookers fit was excellent, no clearance issues, slipped right in, no low hanging pipes scraping the road, no front end parts to take apart to install them.