Sorry, for the late response. The paperwork that came w/ my carb says 3/8 gap, 1 1/4" drop. Remember don't bend the arm/use the tab. Also, if you turn the carb upside down, small parts "WILL" fall out.
I'm hoping to get some help from the DS II swap "experts" out there...
I decided to swap out the computerized TFI ignition and feedback carb on my 300 I6 in my 1985 Bronco. I found this thread before i even started and used it to gather the parts I needed. I went ahead and bought everything new with the exception if the wiring harness, it came out of a junkyard 1978 F-150 with what looked to be a 302 (definitely a small block) but the plugs that go to the main truck harness do not match up with mine nor do they fit any description that I found in this thread. Everything that I've read in this thread show the wiring harness to be a direct plug & play but I'm not that lucky i guess. I took some pictures of the problems I ran into.
These are the 3 connectors that I have coming out the firewall
These are the 3 connectors on the end of the harness form the junkyard truck
This is the junkyard harness plugged into the ignition box
This is a plug from the firewall harness plugged into the other connector on the box
These are the 2 left over firewall harness plugs that don't have a match
These are the 2 left over junkyard harness plugs that don't have a match
To add to that, you need to be matching up wire colors, ignoring the connectors.
IIRC the oval-shaped two-prong connector is for a dash-mounted tachometer.
If you've been researching a DS2 swap, then surely you know the red connects to the white and the white connects to the red.... in a certain location under the hood, I believe where the module connects to the truck harness but don't remember for certain...
I did the DSII Swap on my 85' w/4.9L. I looked at a lot of harnesses...the ones from the late 70's were different (gray firewall plug, etc) and some of the early 80, 81's were hit or miss...I kept finding CA Emissions Trucks. The later years 83, 84, 85 went to DSIII. I used one from an 82 (plug and play).
Where I am...Nevada...not all 80-84 trucks had the right harness...all 82's did though. And of course a V8 harness will work (just a bit longer/same plugs).
I agree, 82-83 truck are the best choice, but still look at 80-84 trucks.
On a V8 truck you have to cut the black wire on the tach connector, between the DS2 IGN box and the plug, to get the tach to read correctly for a six cyl.
The older harness, pre 1980 will still work with some extra wiring work. It ends up being a mix of the old original harness with the DS2 harness.
I'm in the middle of this project myself (computer delete, Duraspark convert) and I'm going with the "make my own harness" route. The biggest thing I think is crucial is connector integrity, that is good, tight and accurate connections. I'm using Weatherpak connectors (because I have a bunch) - but a quality mating connection will insure your ignition circuit works, is easily repairable down the road and wont give you trouble-shooting gremlins as you continue with your project. My two cents. Russ