I not sure what others have used for bolts to mount a Dyna muffler to the stock savage mount. But I found these worked great for my application. Saved me time trying to find bolts that would fit in the narrow Dyna channel.
I didn’t have to grind down bolt heads, or find a way to get a wrench in to hold the bolt head, to make sure I got it tight enough.
I bought (2) each of these, hoping that I could use both to bolt the muffler on. Turns out I only needed one, so I have a spare to go with the other Dyna muffler.
These are HD P/N & they cost me about $5 from the local HD dealer, they are for a 2009 Dyna Super Gilde.
P/N 5445W- Carriage Bolt
P/N 7531- Locknut.