i need to replace my rotten mufflers in order to get around to a proper carb sync. (1980 cb650 engine with PD carbs). i'm thinking of going with these....

they are only 19" as compared to the 24" ones that are currently on there (and full of holes). i'm wondering if there is going to be a drastic back pressure change, as i'm not at all interested in rejetting.
also, if anyone has a picture of their bike with them mounted i'd be curious to see it.
thanks.