ok expert thus there not the same size thus they are pratts.
can you tell from the air which is which? i think not all pratts sound like ........pratts
sarcasm off
btw where is your soundpack? 
I hate to break it to you, but I've been up close and personal with a P-47D-40 and a DC-3 (both at Hooks airport in the greater Houston area), and the engines sound vastly different. The R-1830 is much older technology than the R-2800, and it has fewer cylinders.
I've got complete engine runs of both, though unfortunately I don't have one for the R-2600, which is different from both as well. I know this because there was a TBM-3 at Hooks for a while, and they'd do engine runs and basic maintenance. Wright R-1820s sound quite a bit different from Pratt & Whitney R-1830s, as well.
Don't get up your own bellybutton just because you make sound packs. I've been making them for several years now, and I find that it's better to stay on the side of reality than infatuation with your own work. It would've been far more considerate of you to simply acknowledge colmbo's statement.