If I remember correctly, the Fords for 38 & 39 were similar but with obvious differences. The throttle & choke rods come through the firewall behind the dash and have a slotted fork attachment so there is some adjustability. The flat blade was attached to the rod fork with a screw that could be tightened in a position for best function. The dash had a slotted grommet that fit in the hole for the knob to pass through.
Here is a link to the throttle/choke rods at the DC site.
https://www.dennis-carpenter.com/en/...-throttle-rods
DC mentions it fits Mercury but it may need tweeking. I only believe it when its installed and working.
I use a but load of different type cables on the helicopters and they aren't near as reliable as the old Ford set up like that.