ORIGINAL: sideoftheroad
With the Top Flite In Cowl muffler you posted, I found on eBay you can buy the header by itself. Part # TOPQ7920. Probably could drill/tap the nipple for vent but for the cost of the header by itself you might as well buy the whole thing.
Yup and even if you don't use the CAN, you could always use it in a future project.
Yup I've seen it used for that very purpose. It's loud though, but not quite as loud as no muffler or header.
You can also hacksaw that down to any size you want.
I would pull my P40 out and check the fit of the TopFlite Can for you, but I cannot do that for another week or two.