I recently converted my 69 from a powerglide to a th350 and everything went in fine except for the shift arm linkage. The linkage looks like a box with two sqare prongs. This will not fit with my shift cable. Is there another shift arm linkage I can buy that will allow this to fit??

Console shifter? Column? Go to www.shiftworks.com. (http://www.shiftworks.com.) They probably have what you need.