I did something similar to my return tube. It would be a quick fix for VANS to work with Lycoming to have the return tube shorten at the factory. I had other issues with two of the other return tubes rubbing up against the lower heat shields on cylinders 1 & 2. A slight twist fixed the rubbing issue. But, a quick note to Lycoming QA from VANS would fix this.
I doubt this would happen (but I don't know whether it has been tried).
A lot of people assume that Van's is a huge customer of Lycoming and therefore has the pull to get them to make design changes, etc.
Van's does buy a lot of engines compared to many other OEM's but it is still only a small portion of all of the engines that Lycoming produces.....
I have posted about this before but will again for those that have never heard.
The drain back tube for cyl #2 is the same part that is used on a lot of different Lyc. engines (4 and 6 cyl.)
When the original RV-14 Snorkel was developed, its final shape cleared the standard drain back tube that was installed on the first IO-390 that Van's purchased and installed in the RV-14A prototype.
When the EXP119 option was developed, the orig. snorkel shape was used as the basis for the new snorkel that had to be adapted to interface with the AFP200 servo. This new snorkel cleared the #2 drain back tube on the first EXP119 engine received from Lycoming.
It wasn't until a second EXP119 engine was purchased for the RV-15 prototype that an interference was discovered.
What changed?
Nothing was changed on the Snorkel so the only possible explanation is that the drain back tube installed by Lycoming is not always the same shape.
Not surprising really since in most installations there is no clearance sensitivity on this part.
Knowing this, it seems the manufacturing tolerance for this part is fairly large so even if Van's was able to negotiate a design change I don't think there is any assurance that every one would still clear the snorkel (Those of us at Van's that worked hands on with the engines had been prodding them for years to quit using the stupid screw clamps on the drain back tube coupler hoses, and switch to constant compression clamps. Last I checked they were still using the same clamps they always have
)
When we were under a time crunch to finish the RV-15, and we had begun to hear about builders having an interference, we took the opportunity to proof out the Aircraft Specialty custom tube and confirm it was a viable option for builders.
Another option that has been tested successfully is cutting the flair plus a small amount of length off outboard end of the tube, re-flare, and then make a very minor shape change bending by hand to get it where it needs to be.