I have a 1965 Skylark Convertible. From the info plates it originally came with a 300/powerglide, but by the time I got the car it had a Buick 350/TH350 swapped in.
The question I have is regarding the core support: Is there more than one size of core support for the Skylark? I bought what I thought was the right radiator per the Griffin and Summit catalogs, but it is too wide at 33" overall. I saw the earlier posts here that recommended the Griffin 1-56242XS and it appears to be the right size. As I measure my core support I have 27.5" wide x 20" tall and depending on which edge you measure between 2.5" and 3.75" thick.
I'm in a return battle with Summit and just trying to make sure I didn't misread the catalog or that there is another support out there that would work with this radiator.