700R4 Conversion Help

['68 Short Step]

I have searched the forum for a while now and found a lot of answers but still need some help. I took out my th350 the other day and I am in search for a 700r4 to install. I found a good one local on craigslist that is from a 1991 suburban and has the electric speedo. I found a lock up kit from monster transmission but the 700r4 housing on their youtube install video looks different from the one im looking at. Here is the trans I am looking at and also the link to the monster trans video.
here are my questions.....

is it difficult to convert it to work with my mechanical cable speedo?

what is a good priced lock up kit that will work with this trans?

what year model trans are they using in the monster trans video to make the install work with 4th gear oil port?

LINKY

How to Install a Lock-Up Kit 700R4 | Curt's...