rad and fan!

If you go to rockauto.com and look up 1970 340 dart radiator here is what you get

http://info.rockauto.com/GoDan/Detail2.html?www.pliii.com/productcatalog/catalog.asp?partnum=433526

Then take the part number 433526 to you local autoparts store and see if they can order a radiator for a 70 340 dart with the above part number. Or just order it from Rockauto and pay $151 plus shipping.

Also note that I gave you the number for a 1970 340 dart, not a 73 dart sport 340. The reason is sometime after 72 the heavy duty cooling cars (340's, A/C cars, etc) when to a wider rad with a different front radiator support (actually just the sides are different and the opening is bigger). So if you ordered a 340 rad for your year of car it would likely be too wide. Again I am not sure when they went to a wider rad on H/D cooling cars, but it could have been 73. any how thats my 2 cents