Jimz66
For interior differences I'd have to do a lil more research. In all I really do not think that there was a major change. OK upgrade w/ radio sys, gun sight upgrade,arrangement of boxes ect. Like I said I have to do some lookin
This will be from memory.
As for the outside there were some changes. The SBD-3 had no Yagi Radar Antennas hung from under the port and starboard wing like the later.
There are "three" cowl flaps on each side of the cowling. They start from the ending point of the gun barrel channel(top of cowling) and end a lil more than half way down past center of the cowling(sorry dont know the length/width by heart) The SBD-5 had one cowl flap up at the top.
During the course of production of the SBD-3, a twin .30 caliber "flexible" MG replaced the single .30 that the radio operator used(this is your choice on what variant of the 3 you want).
Just below the front radio mast antenna(In line) there is a ventilation slot panel that is fatter than the SBD 5 which was a bit more narrower (same length thou)
I am sure there is more ya gonna have to do to change it from a 5 to a 3.
This again is all from memory and right now I dont have any of my ref's on the Dauntless near by So I'm sure that others will lend a hand and help out.
Off the top of my head here are two ref books you can get/use in your build.
[b]In actiion "SBD Dauntless) #64
In Detail & Scale Vol 48
Would like to see the SDB after completion
Flaps up, Mike
If you would listen to everybody about the inaccuracies, most of the kits on your shelf would not have been built Too Close For Guns, Switching To Finger