Clutch fan

It's hard to say if it will be adequate for your stroker, but it's probably worth trying.

The idea of the clutch fan is that the fan spins slower than the pulley is turning. This means it moves less air at high RPMs, so it doesn't use up as much HP. This is all good, but the thing is, there are different clutches, some of which have thermostats, and which spin at different percentages of the pulley speed. So the one that worked for a stock 340 may or may not work for your stroker, depending on how much power it puts out, and where it runs in the RPM range (i.e. gearing). The water pump and radiator are other factors, of course.

You will probably just need to try out your cooling combination and find out, if you aren't committing to some kind of aftermarket package from the get go.