Yes, you're right. It's the early borg warner I have. So a C3 and its associated starter motor is what I should be chasing.

Hi Rat.  I know this is an old post but you appear still quite active here so hopefully you will be able to respond.  I was looking up torque settings for Flex plate bolts when I came across this post.  It pretty much proved to be a show-stopper because I have a similar scenario, putting 1600 to replace 1300.  My Escort does  have the C3.  Calculations show a 4mm difference in block to Flexplate clearance.
 
Did the spacer solve your problem?  I am looking to do the same as I dont want to encounter your starter problem late in the game....

Yes, the spacer was missing on the crank. Once I removed it from 1300 crank & installed on 1600, everything was perfect

Oh?  you had a spacer on the original 1300?  I don't believe that is the case for me unless it appears to be part of the crank end.. I will recheck when I get home this evening....

Arg well what a n00b I am.  Sure enough, the crank ends looked different because the 1300 had a spacer on it. Gah

So, did you find that you needed the new dipstick guide as suggested by Willy Pete?
 

I used 1.6 sump & dipstick. The tube I'm not sure about but I don't think there were any issues there