Cool Bob!!! Looking forward to seeing it! Interesting approach to those prop tips I haven't tried yet... might give that a whirl on my next dash-2.
I'll try to find some pics very quickly for you, but the exhaust left little black on the plane... just immediately around the exaust tip itself. Over the wing it faded more to a whitish grey and it was very light at that. I'll bug out of here and see what I can find in a hurry, hopefully I still have them in photobucket!!!
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I'm having trouble finding them, but you might find these wartime shots helpful.
http://www.warbirdsresourcegroup.org/NARG/dauntless.html
There is almost no exhaust streaking... I have seen pics with it but I am still on the path for them now.. more later
non-wartime but decent shot of exhaust:
http://fotodj.com/pages/reading/Wb048d.htm
It's wierd but the wartime shots don't show that much streaking. I'll keep looking...
!!