I have a 78 truck with an old clutch fan. I noticed that when I turn it off, the fan kept spinning for about 5 seconds after I shut off the engine. So, I was going to just buy a flex fan. I started thinking, and I decided that I would prefer an electric fan to take mass of the pully. My question is - How do I do the conversion? My original clutch fan was 19", so do I have to find a 19" diameter fan or is there something else I do instead? Also, will my stock shroud fit it?
Thanks

 

...http://www.flex-a-lite.com/

If anything you will save gain mpg in city driving and the AC will be cooler in town.
Do a search here too. Some do not like the FAL controler but if you do it right you should be OK.
You most likley use a dual fan setup.