Here's a conversation that I had with my kids, and perhaps it applies here.
NEEDS versus WANTS
I'd do whatever you absolutely NEED
to do to meet your immediate transportation needs. Get it runnung, make it SAFE to drive.
The next time you have some spare cash, invest it in what you WANT
Buy a "running core" (always the best idea, IMHO) and take it to a trustworthy engine machine shop, and ask them to evaluate it's viability for a rebuild. In the case of the 450,000 mile TBI ... it may be running pretty good right now, but the bores might be tapered to the point that they can't be rebored to the maximum limits of the casting. (Now it's a boat anchor.)
ANY core should be hot-tanked and magnafluxed to check for cracks, then measured up for taper and warpage. A 4-bolt main engine is preferable. It should be align-honed and everything "squared up". Call it the "engine foundation" if you will.
Once you have verified the integrity of the block, you can decide what you want to use for a rotating assembly. i.e. crank, rods, pistons, cam, bearings, bolts, etc.
You can take some time doing this, and make good decisions, because your immediate transportation needs have been met. If this process takes a couple of years or more ... as your budget permits ... it's not a big hardship.
Putting aside some cash isn't as hard as you think. It just means sacrificing some of the less important (to you) expenses.
Here's my own personal "sacrifices"
Pack a lunch instead of going out.
Quit smoking or going out to the bar ... neither of those are good for you anyway! LOL
Ahhh never mind ... nobody is ever going to give up on that.