If you box is original keep it and give them another core or just pay core charge.Any core. shop.advanceautoparts.com/p/cardone-steering-gear-27-6581/10314420-P?searchTerm=steering gear $149. used discount and perks it was about $112.This is the 1 1/4" good replacement until I rebuild mine.
Direct replacement is, I believe, 67-72. I just got a Lares rebuild from Rock Auto for $150 (core charge was $250). They were the only remanufacturer that got good reviews on the boards. I sprung for a "stage 2" box years ago but wasn't that impressed - it felt the same as my 50,000 mile original.