681F 6015 DA

Would it be safe to assume that a block with this code accompanied by a twin choke weber would be from a pre-emmissions 1975 escort? 1.6 High compression?

I've trawled that info already Jamie with no luck. I saw the reference to 1968-69 for the 681F block. It might be from a MK1 1600? Which model was that?

2737E-6015 (in 1st Mark 2 Cortinas)

681F-6015 (in later Mark 2 Cortinas)

691M-6015 (in 1st series Capris, Escorts and later Mark 2 Cortinas)

711M-6015 (in later Capris, TC cortinas, Mk 2 Escorts locally) and
the Mark 1 Escort Mexico in UK.

All the 3 early blocks used the 8cc chambered head, as well as the 1st
series Escort 1300GT motor, all other motors (1100,1300,1600) used
flat heads, with several different valve sizes.

All the 1600 motors used 2737E conrods.
All the 3 early 1600 motors used 2737E cranks, the 711m motor used its own crank (711M).

The 2737E and 681F have round main bearing caps.
The 691M and 711M have square main bearing caps.

Prior to the 691m and 711m square mains caps being released,
people fitted machined steel caps to earlier motors, there is no
need with the later caps as they will take 200+ HP.

All 3 early blocks use small stem cam followers.
The 711M block uses the large stem cam follower.

hope this is of some help

cheers
Brad