There’s a cult following to your suggestion, and I’ve read the ‘sequential debate’ in numerous forums - but getting a sequential system adds a BUNCH of complexity and cost over TBI. Things to ponder:

SEFI requires port injection, so there’s $300-600-worth of additional expense on the intake tract. You also need to add some type of cam sensing, or at least a crank trigger and some programming to count the revolutions correctly. GM TBI units are modifiable, fairly rugged, and dirt cheap -- even the 454 ones are reasonably-priced. Depending on one’s power requirements, a tweaked 454TBI setup with a Megasquirt2 can get you injected at around 350-375hp or so (and with spark control) for less than $1500.

Also, sequential loses its benefits above ~3000 RPM anyway because there isn’t enough time to squirt sufficient fuel only when the valve is open (those benefits were mostly for the OEMs and emissions regulations). Furthermore, squirting/wet flow on a closed valve (as in a batch or TBI system) gives the mixture a hot item to vaporize from (and vaporization is good!), so it’s a nebulous scenario.

Fuel spraying from an injector becomes cooler, but the wetflow thru a warm intake manifold has had a longer time to atomize. Plus, if you want to squirt at a closed valve in a bigblock Mopar head, you better find injectors that can squirt a curveball!

After I get 3-5 systems under my belt maybe I’ll feel differently, but for now a TBI unit is essentially a carburetor that’s fully-variable, almost fully-programmable, and won’t boil the fuel out on a hot day. That’s still a huge step upward IMHO, and a great way for a beginner to cut their teeth (or retreat if necessary).