Need info on muffler flow

[Michaerl503]

My boss has a 1972 Chevy with a 350 in it, mild cam, shaved heads, etc. He went from a stock 2 into 1 exhaust to a dual system with a crossover (H pipe).

What he wants for me to do is to find info on muffler flow rates on the internet since he wants to reduce the flow on the dual system as he feels it is too high.

I have been tasked with finding this info, but so far all I have stumbled upon various postings showing total CFM, but they are all aftermarket muffs, and I need to know what the stock muffler flows as a reference point.

Can anyone point me in the right direction? Is there a good site that has flow rate listings for mufflers for this size engine, specifically what the stock one flowed?

Thanks