Rebuild or replace?

MOPAROFFICIAL said
I'd build a 318 , they're cheap. Stick the 273 in the corner of the garage.
That way you dont have to update everything else. Though I might do a street convertor, like the 200 kind, while you're there...

Unfortunately, I think the 67 904 trans has a different input shaft and convertor hub. I'm not sure what convertor is available for a 67 down 904.