Putting a 351-W in my 66 and wanting to go back to a 4 speed,a local pull and pay has a 85ish F350 with a 6.9 diesel and will that 4 speed bolt up to a smallblock.

 

That should be a T19, all synchro, fairly close ratio as boxes like that go.

https://www.novak-adapt.com/knowledg...anual/t18-t19/

You need a proper bell for your 351W, which should not be hard to find. Trans to bell pattern will match. Input shaft specs and bearing retainer size need to be checked but you are probably good there too. Is your '66 a stick already? Do you have your clutch figured out?

 

The 66 was originally a 4 speed and still have all the clutch linkage and have about all I need except for a flywheel that is available from Autozone,the trans in the F350 has the U joint that bolts on but I have seen a slightly newer trans that is made for a slip yoke like on a automatic which is really the trans I want since I want to go with a one piece drive shaft.