This probably belongs in the WTB section, but thought I’d post here instead:
Trying to help Brett A., he has a D6C 74A that he wants to add on a decellerator; 
Parts group #8M7394?
he will pair the D6 with the 60 pan I sold him last year; he likes being able to lower his engine speed around corners and ends without using the hand throttle, which makes good sense to me.
He is looking to buy the parts, didn’t know where to begin, so I said I’d post for him. JM

Hi, Juiceman.
I suspect that any GOOD Cat dealer would be able supply those parts. Also:

www.tractorparts.com/

Or Chad Enyeart - wyocat - antiquecrawlerparts.com/

Hope this helps.

Just my 0.02.

I made a post about that same parts group in the WTB section myself a while ago for my 74A. I called a couple of salvage yards also. I'd be interested to know where he gets his parts from, if they can be found.

The dealers around Houston dont have any interest in parts for older cats.

Hi, Juiceman.
Another possibility - Quinn Cat at Fresno may still have a used parts division. I KNOW they did 12 months or so ago.

Just my 0.02

I did some posts on that a couple(s) years ago....yes it is nice to have a de-cel working or something similar...it's like a brake and more gentle on things..
-don' have any part numbers for pieces but super easy for what is needed..