ENGINES!!! What would you do?? Check it out!

[71ChevySS(straight6)]

Hello again! So, I've decided to take action. I'm pulling my 250. It needed a head gasket and intake gasket, plus it had low compression in cylinder 2, and it was choking itself out with antifreeze-tainted oil blowing into the breathe tube on the valve cover. At 44 years and 133,000 miles, it finally bit the dust.

The dilemma: what do I put in it now? I have approximately $2,000 to put into this.

-A fresh 250 would be the cheapest, easiest option. All the old parts (carb, hoses, fuel lines, radiator hoses, etc) would bolt right back up. Since it's cheaper, I can afford to splurge a bit and buy a header or headers, do a dual exhaust, maybe go up to a 2-barrel carb, maybe a Clifford intake, and possibly a performance cam.

-A 350 would be the traditional route to go. But, it would require different radiator hoses, fuel lines, motor mounts, etc.

-I found a freshly rebuilt 283 on Craigslist recently. It needs a lot (carb, headers, serpentine assembly, distributor, etc) but the guy only wants $300 for it. Are 283s any good?

-I have also considered a Cummins swap. Practical? Maybe not. Unique? Very. I'd have to upgrade suspension and completely redesign electrical and fuel systems, along with just the struggle of making it fit.

I will definitely swap out the rear gears. Currently, there's no way they're not 4,10s, maybe even 4.56s. The truck has to rev about 2500 RPM to go 45 MPH. So, 3.73s or 3.65s?

What about transmissions? The NP 435 has seen better days...
What do you guys think? Any suggestions? Thanks!