I have a 68 rs. Could someone tell me if the
700R4 fits (any clearance problems). And If the speedometer cable will hook up.

I put a 700R4 in my '68. It was a tight fit, but I didn't have to beat on anything. I used the speedo cable that I had on the TH350. I made got it to thread into the housing on the trans, but it had to make a sharp bend to do so. It didn't take long before it broke. I bought another one a few inches longer, it works fine now. I've answered some other questions on this site about my TH700R4 if you are interested. Use the search by user name. Good Luck !

Thank You.