You might do better buying a proper rad and some high flow fans and also putting your pickup for your fans for your fans in a better place if this dont pan out.

I run a dual pass rad, HV dual spal fans and have one fan on the Temp sending unit and the other on a manual toggle since I hardly use it but can over ride all with another.

Cruising with a 5200 vert and 4:30 gears the one fan shuts down in a few minutes at over 45 mph using only cruising air to cool on a big inch small block thats 1/2 filled.

I would try what grizzly said and if there is an improvement you might consider a bit better shroud and fans more purpose made for your needs vs boneyard parts.

My t stat deal is a 165 that I have in the intake cross over, so fan comes on then and never goes over 185-190 on the temp gauge.