I had a 66 with a 351c and I bought a set of headers from JBA,they had a tube from each head that swapped sides,one under the oil pan the other under/behind the bellhousing. They sell these in different diameters as I used 1&3/4 but 1&5/8 through 2" are available. The quality is high,easy installation and helped Me make 450hp with Allen Root ported heads,holley dominator intake,holley 750-4010 carb and a 292 comp magnum hydraulic cam.After the headers exhaust was simple 2&1/2 with a crossover and Dynomax superturbos and 3" tailpipes.I hope this helps if not try Doug Thorleys 69-70 boss 302 headers which should also bolt up to Your cleveland heads. Good Luck!