66 230 rochester 1bbl dual carb linkage

[papaws66]

so i'm wanting to put dual headers and dual carb intake on my 66 230. i've found pretty much everything i need to do this (haven't ordered anything yet) but i can't find a dual progressive linkage for the rochester 1bbl stock carb, as i am planning on just buying another to go with the one on it. i want a progressive linkage to keep my low end torque.
so the question i have is: Where can i find a progressive linkage for these carbs?

also.. with the exhaust, i'm planning on straight piping it out both sides and coming out at a 45 angle in front of the rear tires. is that going to be to loud in the cab to stand? i definitely want people to hear it and turn their head, but i don't want to be miserable while driving..

any help would be great! thanks