Local salvage yards are a great place to look. Sometimes the driveshafts get smashed up when they use a forklift to carry 'em around though.
I found a 4R70W automatic transmission from my 2001 f150 4.6l 2wd. Would that be a good transmission?
4.6 and 351 have different bolt patterns
I did not know that. You sure? 351cleveland
All 4.6 engines (and other mod motors) have a different bolt pattern from the Windsors, which have the same bolt pattern as Clevelands. You can’t use a 4.6 transmission, sadly. Any 5.0, 351, or V6 cars up to 2001 would work though. V6’s are a great choice, because they are so common.
Later, the 351M and 400 usually had the “Big Block” pattern which suits a C6, but won’t work with a 4R70W or any of the new transmissions either.
Here’s a pic of the 3 common ‘old’ patterns, all of which are very different from the “mod motor” pattern.
Just to add more info., al-tho the 351M ,400, 429and 460 are considered “Big Block” they are of the 385 series and do not have the 390 427 428 FE big block bolt pattern.
Thanks guys
I asked him to measure between the top to bolts and he did. They were 5 1/8”. I thought that meant it would fit
Mod motors are their own weird pattern.
I love Mustangs. They have a ton of great parts for my Cougar! 
We used a lot of our less attractive siblings for parts for sometime.
-Keith