mikeynags

What do you guys think of them? Are they good or should I stay away?

67 GTX

depends
if you are going for stock, then stay away

78D200

I ran a Flex-a-lite fan on my J10 and cracked a cylinder head while wheeling it. They are not good for off-roading. For onstreet driving though, they are not bad, but like Matt said, if you are all stock to mildly built, start with the stock fan or go with an electric fan. There are other ways to cool a motor also.

Frank the Tank

No offense, but the flex fan is pointless. If i where you, i would get a light weight fan with a new clutch. The fan clutch prevents the fan from spinning as fast as the motor at high rpm, but it still pulls air. An electric fan is also a good idea, but a little more expensive

Archer

Gents -

Sorry guys, we've been using "flex" fans (at least if we're talking about the same thing) as far back as I can remember. Clutch fans don't generally provide enough air flow and electric fans can be a pain as you have to A, wire them and B. need some kind of sensor. If used in combination with a motor driven fan, you don't want the flow rates competing.

A good light weight / high flow flex fan, IMHO has always been the way to go.

Archer