40C tracks on a 420C??

[420C-Mike]

Continuing to learn about the "toy" as I start to embrace the many 420 crawler rebuild projects. Knowing I had considerable wear with apparently a link already removed (30 links each side on a 420C 4 roller), I have resigned myself to make a sizeable investment and have Lavoy rebush/pin my crawler belts. I have the crawler up on jacks and have been painfully removing all pads as many are bent and all bolts need replacing. Some still had heads that the impact wrench could catch, others are rounded, some of the nuts rusted and "welded". After a lot of "effort" and many different methods, I have only a dozen pads left to remove but will get there.

Most of the links seem in reasonable shape although a few have some notches around the bolt holes and a handful have elongated holes for pad bolts. I thought I was doing well as i found a few "used" links online and assumed they could be rebushed and used to replace the missing link in each belt a replace the few that seem questionable.

As I looked closer this past weekend, I found the replacement links seems a bit larger/heavier than those on the machine and initially thought the replacements were incorrect. On closer inspection, I now believe the units installed on the crawler may be from a 40C rather than 420C as the pins are approximately 7/8" whereas the replacement are approximately 1" which is what I believe is standard on all 420C's (my unit is s/n 84221).

questions:
1) Are my assumptions correct that it appears I have 40C links on a 420C? Is there anything else I should measure?
2) Is this possible? Could this be original factory supply?
3) Are the Drive sprockets any different between the 40C and 420C/ (diameter/number of lugs
4) Can I rebuild the "40C" links (assuming I can find some used 40C spares) and use them on my 420C?
5) Should I expect problems with this arrangement?

appreciate all comments and recommendations. I have some pics but have not yet figured out hot to link/post

Mike

[Lavoy]

40 is indeed smaller links and smaller pin and bushings. The pitch is the same, sprockets are different due to bushing diameter and just strength in general. The 40 links are also shorter, so may or may not be some interference with rockguards.
Torch is easiest way to remove pads if the heads are bad at all.
Lavoy