Thanks for your replies and help guys. While I’m aware of many of the details associated with radiators and cooling systems, I’m far from an expert. Your formulas and other technical feedback are helpful as well as personal experience.

I started my project by finding an OEM (new) radiator that would simply fit within the core support and “seemed” adequate based on the original application for that radiator. The only radiator I found that fit the need at that stage of my project was a Modine 3-core model made for 67 Mustang w/302, AC and automatic. However, I’m some 3 years further into my project and have upped displacement and horsepower significantly (imagine that!). I have since found that not only is there a 4-core version of the same radiator but know of many aftermarket radiators made for early Mustangs.

However, it is hard to pass up the low cost and easy availability of the many cross flows on the market. Hence my original post question. The Mustang radiator is small (roughly square @ 18” x 19”). I have plenty of room to go further in the vertical direction and as a result, have been looking at an 18” x 26” which appears to be very common. Certainly, any trimming of perimeter brackets is nothing and expected. I’ll be using an electric fan and shroud package from a Taurus. I had a plastic flex fan in place but have opted to go this route and know several using the same package with very good results. The shroud is also very smooth in appearance which makes it blend well with the rest of the parts. I had the same thoughts initially Mike but gave in to the fact that all newer cars use electric-only cooling fans. I also like that they only run as needed which is usually never while running down the road. Parasitic horsepower loss from mechanical fans can be quite large.