I had the front bracket on a '75 250, but no rear lift bracket, so I designed one using the stock throttle linkage (2 bolts) and copied its bend.
Then I worked with Clintonvillian who converted my measurements into DXF/DWG and I cut out a new set.
Rear
Front
There is still a problem though, the spot on the block where the front bracket bolts on has different bolt patterns between the 250 that I pulled the original measurements from, and the 1970 170 that I am using in these pictures.
But how many of us really use more than a single bolt hole for the chain anyhow?
You could use the single bolt/loop from the next picture.
The top 3 brackets on this are for lifting sixes, Clintonvillian designed the largest and smallest ones for lifting a 300, the other one is a fresh cut rear small i6 mount.
The single bolt/loop could also be used for older motors with the round log, but using it to connect to the rear most exhaust manifold bolt.
If there was interest, I could buy some more 7g and have a few cut out.
-ron