I think that the difference in diameter may be because of the fact that Hasegawa's F-16 nozzles(both the GE and P&W) have a part of the Viper's aft fuselage molded along with it. That section tapers down to the nozzle's diameter further back and that doesn't happen with the Eagle.
I say this because i'm using Hase's F-16 for the F-16W build and i had to cut that fuselage section out of a nozzle to be able to have the correct length and diameter to attach the F-22's nozzle and just a few mm were enough to make a considerable difference in diameter.
Regardless, this is looking like quite a nice conversion and it'll probably look very cool when done! 

Finally it's done, but unfortunately it's a tad tail heavy. The slightest gradient, it will sit on its tail. Got to fix it later  .













Comparing with another whiffy that I'd done a long while back

I'm not surprised it's tail heavy with those 2 monster engines matey 
The cool thing is those engines look just right on the 15s frame so bitchin build man 
This I like a hell of alot but most things with 2 stonking big engines does 

 

That does look good 

                

 

Wot they said!!!!
  

Someone on here did drawings of F-4 and F-15 with swapped wings.
They looked good.
I thought i'd saved them but apparently not.

Very nice!  

BEAUTY! 

Quote from: zenrat on January 06, 2023, 04:37:13 AMSomeone on here did drawings of F-4 and F-15 with swapped wings.
They looked good.
I thought i'd saved them but apparently not.

ysi_maniac could do such a thing https://www.whatifmodellers.com/index.php?topic=29716.0

Looks GREAT!! 

I like it!