IMHO removing the inlet and replacing it with a proper plenum and changing the exhaust manifold will give you damn nearly as much power as any of the shonky carb setups, beaten only by properly setup 45s.

I don't see how you count a grand extra to fit efi (unless you mean to remove and replace your current setup rather than the position the OP is in)? ignition only ecus aren't that much cheaper than the full fat version, loom is similar again. Manifolds are the same price, throttle bodies are as much as carbs.

When it comes to setup, your ignition map is identical in terms of hours and effort, and properly jetting a set of carbs on the rollers takes as long as making a fuel curve (and by definition can never be as good).

The only way carbs are cheaper is if you dont do them properly, by which I mean secondhand carbs which are probably worn, approximately jetted for the car and balanced by ear, on whatever trumpets came with them as opposed to the correct length, combined with some horrible ignition setup like you describe delivering a worse ignition curve than any distributer (which were never great to start with).

Good carbs cost the same as efi, bad carbs aren't worth having unless the rules dictate IMHO.