I just fitted a pair of 26 inch Smitties to my 54 h/t. I fitted Graham cast iron headers with the Smitties mounted close to the front, 2 inch pipe in, 1 ¾ inches out. Good sharp rap for an otherwise stock mill at anything over 1,200 rpm - maybe too loud for a cruiser, we'll see. When I looked under the car, the mufflers were fitted backwards, with the inlet arrows pointing to the rear. When I called the muffler shop, they said that they fitted the mufflers so the louvers inside were facing into the gas flow. So, before I take it back school me, are the louvers meant to face the rear, or are the inlet markers wrong on my mufflers, or should I just turn up the highway hi-fi and sit back and relax.
leave it as is,you will be ok.My muffler guy always asks me,"loud or quiet?" meaning the louvers with the flow or against it.
I also have Smitties on my 54 Chevy! I beleive the arrows your talking about are meant to show the direction the exhaust flows or exit's (arrows pointing toward the rear of the car) rather than it's inlet. Pretty sure you have them on correctly rather than backwards. These are how I put mine on!