To the best of my knowledge there were 164s produced in the 1975 model
year but not 140s. The 1975 B20 was an "8-bolt" B20F with CIS injection
system (like the 74) however I think it had a little bit lower CR and also
electronic ignition. The electronic ignition system is highly prized.
The CIS system is OK and once you get everything right it is relatively
trouble free. You can mill the head and get the CR up so that it is
not much different from the B20E. A good cam helps it a lot.

As far as "metric" I once bought a 1975 bare block to replace the block
I split while I was in Panama. I found that the maincap bolts and the
bellhousing bolts are metric but I don't think there are any other metric
threads in the block, and the main bearings are the same as the 6-bolt.
After I finally found the bolts for the maincaps and bellhousing (in Dallas)
I was able to get my engine back together so I have an 8-bolt block with
6-bolt innards.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma