Yes, because the converter snout/register goes into the front of the trans - match the converter to the style snout register on the trans year that you are using...
The back side of the converter bolts to the flex plate and measure the bolt circle for the flex plate to make sure it has the proper bolt circle...
I know some flex plate to converter bolt patterns are 10" and some are 11" on the v-8's.... I'm not sure if slants had the two converter to flex plate bolt patterns or just the smaller one.... (I'm not a slant expert...)