I don’t think you’ll regret it! See if you can find a decent used set instead of going with new. They show up somewhat regularly. As someone pointed out it’s possible to use a 3.8 set up, which has three individual intake manifolds, instead of the 4.2 which has a single manifold. However the Mk10 sedan also used triple SU’s and virtually NONE of those components can be used on an E type. Yet they are often described as being suitable for an E. So if you’re thinking of buying a 3.8 setup ( triple manifolds) run them by someone here to make sure they will fit an E. Feel free to direct message me if you want someone to review. The easiest and safest way is to find a decent 4.2 set. Be patient. You can also place a wanted ad here on Jag-lovers.
Also let people know where you’re located and you may get a volunteer or three to assist. It’s really not that hard.
Here’s a 4.2 set I sold a couple of years ago for $1600. [SOLD] Triple 4.2 E-type SU carb set and manifold