Wondering what individual pieces of sheet metal need to be changed
to go to the bigger radiator. I was looking for an exploded diagram but
can't find one.
One option, if I were to just cut and weld, I could go with even a bigger core.
I'm looking at the car and can't quite tell what is welded to what.

You need a 70-74 E-BODY / 71-74 B-BODY 26-INCH RADIATOR CORE SUPPORT BRACKET CONVERSION. Sorry for the caps copied from an ebay add. Use one in my Challenger and work well.

Hmm, so the drivers side is the same, the 26" radiator is only wider on the passenger side.

You are correct only the passenger side needs to be changed

if you are not worried about total correctness. you can just cut the passenger side support and drill 2 holes for the radiator to mount to and the job is complete.
90% of the people looking at the car will never notice the difference once everything is assembled.

I think both sides are different, We opened up the passenger side only on our 70 Charger to find that the fan was not centered in the shroud.

I think if you look at the part Nos., the drivers side sheet metal also has a different part No.

Just our experience....Joe

I would look at replacing the radiator core support, but that is your choice

If you do change the radiator support just be aware that it has the V.I.N. stamped into it.

The face plate of the core support is what can be changed... not the entire radiator support (unless you want to).

Another option is to contact US RADIATOR... I believe they have a conversion adapter bracket for mounting 26 into 22. They also have a video on doing this swap.

...........OR just recore your 22 in rad with a high efficiency core ( talk to GLEN RAY ) and dont change any sheet metal . I have had one for over 10 years on my 500ci sixpack engin with oem type cluch fan and it runs perfect even on 110+ deg days . Keep it simple !

ShakerProject,
I like that idea, good to hear that it works.

Yes I believe that both sides are different but mainly the PS. I fitted a 26" rad into my 22" core by drilling the extra holes and just spaced it back very slightly to not block off an air path to the extra width.