If you want EFI, I'd really consider doing it right the first time, and building an engine for the EFI, and put the EFI system of your choice on.
Assuming your engine doesn't need any major machining, they are pretty cheap to rebuild. Basically need a set of pistons + rings, bearings, cam + timing chain kit, an oil pump, and seals. You can get all this stuff off ebay for under 800 bucks, in high quality brand name components.
That said, if you want a good engine, the biggest thing that it needs is a good set of heads. I've come to the conclusion that when you build an engine, you need to start with the heads, then choose the other components based on your head selection.
If you went with a set of aluminum aftermarket heads with 60cc combustion chambers, you'd then want to go with a set of dished pistons to set your compression ratio at like 9.8:1, if you still want to run 87 octane, then select an EFI cam that makes power from idle through 5000 rpm, assuming you are running a stock GM EFI system. Can choose a cam that makes more power in the top end if you go with an aftermarket EFI system capable of supporting it. Keep in mind you don't want any valve overlap, and that you want an engine that idles relatively smoothly.
You'd then have a pretty stout engine, that'd be just fine with the EFI, and while it would require tuning, you'd have made it easy on yourself by building an engine that is within the EFI's capabilities to control, and just need to tweak more than anything.
Or, you can just buy a TBI crate engine, put a mild cam in her, and call her good with a stock chip, lol -- Up to how much work you're willing to do