1979 6.2 k5

[hatzie]

Radiators are usually measured to the ends of the core not the tanks.
I used a 4 row 29" x 19" core radiator in my '76. That's prolly 34" or 35" to the ends of the tanks. The problem you'll run into is the HD radiators were taller. I went from something like 16" 3 row to 19" 4 row. The top support is different depending on the core height.

I used a power steering cooler to keep the hydroboost happy.
I didn't get a radiator oil cooler. My oil cooler is an external B&M plate type unit similar to the one GM used on the T400 chassis diesels with modified hybrid cooler hoses (stock on the block married to AN braided from the cooler). Yes. I had to cut the core support to route the cooler hoses through.
The nasty part, for me, was fabbing mounts for the aftermarket parallel flow condenser and the oil coolers so it looked decent. It can be done without looking ghetto or blocking airflow.

I have an NV4500 so the tranny doesn't get a cooler.