Rug Trucker, Let me think a bit. I am almost positive they are the same. I know the bell cranks an such are the same on my 80 sl6 van and my 83 sl6 van. See an hows Dodge didn't like to change things I'm thinkin they are the same or durn close
The last linkage rod from bellcrank up to carb might be abit different but thats what hammers are for right? I used the throttle cable assembly from pedal to carb off a 90 318 van for my 83 slant with clifford,edelbrock etc. The 77 was the last year you could get a big block in the van and they changed the dash and dog house for 78 sooo the off set on throttle rod from pedal to bell crank might be a little diff also. Geez hope this helps not hinders 