I recently took a trip, and flew on an A-319. Like to build a model, but there aren't any kits.
So I did some research, and the word is that the 319 is 12 feet shorter than a 320.
OK, fine, so where do I shorten the fuselage. It helps that the 12 feet in 1/144 works out to exactly ONE inch. But where to make the cut(s)?
This is one of those deals where "None of us is as smart as all of us". And I'm hoping that I'll be the dunce.
According to Wikipedia, "The shrink [from 320 to 319] was achieved through the removal of four fuselage frames fore and three aft the wing, cutting the overall length by 3.73 metres (12 ft 3 in)."
12 ft 3 in = 147 in, meaning each frame = 21 in (147÷7). Therefore, you want to remove 84 inches ahead of the wing and 63 inches aft of the wing. In 1/144, those work out to 0.5833 inches and 0.4375 inches respectively. Metric equivalents are 14.8 mm and 11.1 mm for 1/144 scale.
Or, to save yourself the work of cutting and splicing, you might look for Revell kits 04200: