With mine, although a BBC/T400 the Hedman headers are aligned with the exhaust slots of the BOP cross member.

 

I have some hooker long tubes on my 68 cutlass with an LS3. I had the same problem with tube ends not fitting the stock cross member reliefs on my convertible. The 4L65E I'm running has a trans mount that looks a little farther away from the engine. That gave me a little more room to create funky tube bends through the cross member reliefs. Hooker seems to like to tuck the tubes close to the floor pan, which is good in certain situations. Bad in others. If I was to do it over again, I'd buy the short tube headers for the flexibility. An aftermarket cross member with larger reliefs might be the best solution for you. Good luck.

 

Ordered this: https://crossmembers.com/product/196...mber-hardtops/

Will advise if it works.

 

Received this today. IT FITS!