Needing info on fan blade choice

[grants6]

Gathering parts for my 65 401 and wondering best choice for maximum engine cooling, I believe mine originally had a four blade type? Going with primarily stock 401 with dual quads, new four row brass radiator , is it advisable to go to 5 blade or stock? Thanks

[gssizzler]

A shroud helps also! You can run a 165 or 175 thermostat also ! I have a four core brass copper in my post with a stock 4 blade no shroud right now fresh rebuilt motor and it never has gotten hot! I drove it one day when it was like 95 degrees out!, I wasn't in a parade of sitting in traffic either!

[vinnie]

I had a five blade fan with a  fan clutch on my 401 2x4 stock engine and had issues keeping it cool. Removed the fan and clutch, went back to the stock four blade fan and spacer. Temps now stay in normal range.

[grants6]

Thanks for the info guys!

[WkillGS]

I've been having great results with both a GM blade fan and a clutch fan setup.
The clutch fan was a junkyard find, clutch is from a mid 80's V6 Regal, and the fan was off of a Cadillac.....The Caddy fan was the first I found with the smaller diameter I needed.
The fixed 6 blade was used on GM in the 60's.
I don't have a shroud on either.
I once used a 300 shroud... had to turn it upside down and trim abut an inch off of the circumference of the opening to make it fit the Nailhead radiator. It got damaged when a blade of the flex fan I had on there decided to part ways with the rest of the fan. I do not recommend an aftermarket flex fan!

Edit... found a pic of the 6 blade fan I'm using. It pulls a lot of air!