You've now built your own engine, and put it in the car. Is this correct?
What belt broke? The WP/Alt belt? I see no mention of a broken belt anywhere else in this thread. This is the first mention of it.
I think what i'm pulling out of this, is that your alt/wp belt broke, and you drove the car around. Subsequently, one of the radiator end tanks popped. If this is the case... i'm not going to be mean. The self-ownage is evident. You should really check your radiator cap. It should have been new, along with this new engine you've put together. It should have been the point of failure, not the radiator itself. That's why caps are developed so as to bleed off excess pressure. Generally, this is somewhere between 9 and 13 psi, i believe.
Now that you need a radiator, you can consider some options. The compact aluminum honda radiators are easy to mount, and some have had success with them. I ran one on 1411 for about a year. Worked fine.
Looks like a 1g will work, but most cases i've seen, they're installed in not such a great way, look like sh*t, flop around, and end up causing more headache than they're worth. If you're considering a 1g radiator, i suspect you may be considering a USED radiator. Keep in mind that any used radiator is going to be just about as old, brittle, and potentially shitty as the one you just blew up. I strongly urge you to consider a new replacement, no matter what the cost. I tried running used radiators in 161/2000 some years ago, and kept running into issues. They're old. Really old. If left unused, it seems they sort of "dry up" after a while and the tanks become more brittle as well.
As of the time of
THIS thread it appears that major auto parts stores can get you a radiator. If you have no luck there, i see a 2 row aluminum replacement on ebay for around $200. AFCO Scirocco radiators are a bit more, but I'm not sure they are easy to set up if you wish to keep your A/C. If your A/C is removed, the Afco unit is the way to go.