not true at all
168 tooth were used mostly in heavy duty applications. usually trucks or anything with a t400 trans. most times t350’s had 153tooth, but not always. i have seen big blocks with both, as well as 305s with both. my 454ss was 168 tooth when stock, but with the T56, i have to run a 153 (168 won’t fit in the bellhousing). i also use a 4.3 blazer mini starter (gear reduction) and have had no issues for 6-7 years.