Sanderson make a block hugger for a small block in the 50s Chevys. I believe the stock steering box will not interfere with the Sandersons block hugger headers. https://sandersonheaders.com/shop/?wpce_search=4814&post_type=product
Early SBC front dump or 80s angled rear dump manifolds. I used the latter. A couple pics in this thread Technical - Which current production rams horn manifolds fit tightest? | The H.A.M.B. (jalopyjournal.com)
https://www.jalopyjournal.com/forum/posts/14814313/https://www.jalopyjournal.com/forum/posts/14814313/ This manifold worked well for me. Stock front steering. Car is a Canadian Pontiac Fleetleader and has the Chev frame and steering. 350/TH350 on Chassis Engineering mounts
"Ok…found the info. Part number is 471539 LH from 1979 Monte Carlo, Cutlass etc. with a 305. Hope this helps…Cheers " Bingo....This is a WINNER....Had the same fight to fit 5 years ago with a 350 in a 1949 Chevy Fleetline.