Need new radiator. Best place to buy?

[firefighter]

1976 Chevy truck 4WD
3/4 ton, 454

I had the original radiator go bad about 8 years ago and it seemed beyond repair.
I went to my local auto parts retailer and they didn't seem to have a good source for a new brass / copper radiator so they sold me an aluminum core / plastic tanks one.
Now it's beginning to leak where the aluminum core meets the plastic tanks.
Should I try a coolant sealer or just replace the radiator?

If you suggest replacing the radiator, could you please suggest who might have the most reasonable prices?
I'm not going to go with the plastic tanks this time. I want to go back to the original style brass copper type or all aluminum.

Thanks guys.

[Captkaos]

Find a local radiator supply/repair shop.  They can fix the existing one, and if it cannot be fixed they can sell you a new one

[firefighter]

Find a local radiator supply/repair shop.  They can fix the existing one, and if it cannot be fixed they can sell you a new one

I guess I never thought of that.
The aluminum / plastic tank ones are repairable?
All in all, do you think those are a very good radiator?

Thank you for your reply.

[Captkaos]

I was running one on my 1987 pickup for over 3 years.  I still have it and it is going into another truck once it is running...
Depending on what is wrong, they can remove the tank if necessary and put a new one on...

[Irish_Alley]

if im not mistakin the alum ones from the parts stores come with a lifetime warranty