Thank you for taking the time for the detailed explanation and facts.
I know the first Boss 351 was made in November 1970, so when do you think a ballpark of a cutover from the C5TZ to D1TZ would have occurred?
Question for you smart people. I've read here and on mustangtek that the Boss 351 bellhousing is a D1TE-6394-AA and calls out "71 (late) BOSS 351 Mustang". The use of "late 71" wording raised the question as to what was the casting on "early" bellhousing used on the Boss 351? MustangTek even...