Had to pull the heads this winter for new head gaskets and decided it was time to replace the old Summit house brand (what ever brand they may be) 1 3/4" primary tube that needed to be dented in 3 or 4 places to fit. They had cracked the primary tubes in the first turndown many times and they just wouldn't stay sealed, cracking beside the welded up cracks, so I sprung for a set of Doug's 2" primary ceramic coated. I have never installed a set of headers that fit so well and were so easy to install, cleared everything!! Well, the Kerker header on my Z1R KZ-1000 was easier I guess.
So I say "thanks" Doug's for a great fitting header!
PS: Doug's is the same guy that started Duog Thorley Headers.
PSS: put these on a 73 Challenger with a 440, stock iron heads, power steering, automatic, slapstick console shifter, mini starter off a 318 Dakota