I bought a new 4 core aluminum radiator for 70 camaro 350 manual tranny,only problem is the place for heater core fitting is a female 1/4 ? Should i send it back or

Here is a pic
do they make an adapter so i can get it to the 5/8 or 3/4 nipple needed? My buddy said just put a nipple on the waterpump adapter plug? I like to keep things correct, any help?