The0nlyon3

have an LS swapped 1967 chevelle. It’s got a 427ci LS (dart iron block (not a true LS7)... anyway, I was using a stock SBC factory replacement aluminum radiator that had the tanks top and bottom. It was a 3 row (5/8” tubes totaling 1.875” of internal area)

This came with a radiator fan shroud that allowed for 11” fans (although I used 12” fans just fine. The fans were staggered and I had them wired individually. One came on at 180° and the other 200° (controlled via Holley TerminatorX)... this setup worked okay but would get hot quickly.

I decided to get an LS swap radiator from summit. it’s a 2 row and thicker than the old one. Cooling tubes are 1.25” for a total of 2.5” inside area. I wanted to go with this radiator since the tanks are on the sides vs top and bottom and the inlet and outlet are both on the passenger side. This allows me plenty of room for my air intake tube to run to the driver side. The old radiator top hose interfered with the intake tube. My existing fan shroud doesn’t fit this new radiator as it’s configured differently. I have to make a fan shroud since I can find one that’ll fit this radiator and Summit doesn’t make one for it.

Do you think it would be better to run 1 17” fan or two 12” fans staggered or in line. Here are some photos for reference.

I am leaning more towards the 2 12" fans staggered. This new radiator has a divider inside the passenger side tank. so water goes in from the top, flows to the driver side tank, down and then back to the passenger side tank where it goes back to the engine.

The core has an area of 388.125 sq in

2 12" fans have a total area of 226 sq in

1 16" fan has a total area of 201 sq in

1 17" fan has a total area of 227 sq in

I know CFM also effect cooling as well, but area coverage is important too.

I was looking at a SPAL IX-30102038 12" diameter 1640cfm x 2 would be 3280cfm total or the Mishimoto 12"HD Race Line that advertises 1850cfm each totaling 3700cfm. BOTH OF THESE FANS are 5 blade fans.

A single 17" fan (not a lot of available fans in this diameter) from Derale is advertised to move 2400cfm...

A single 16" Flex-a-lite fan 105390 is advertised at 3000cfm.




new radiator

large 1.25" cooling tubes

divider plate in the middle of the passenger side tank.


These are two Spal 12" fans from my last shroud for the factory aluminum radiator I replaced. If I make the shroud go edge to edge, as the core is only 22.5", I can fit 2 12" fans fine. here they area in line

This is them staggered.

This is what a 17" fan would cover. IGNORE THE ARROWS, I hadn't had my coffee when I drew the coolant flow direction on here. lol

AAIIIC

iTrader: (19)

In my experience it's pretty much impossible to compare fan cfm ratings from different manufacturers, as there's no standardized way for them to measure, and there are plenty of variables that can impact the measured cfm.

Are there any OEM fan/shroud assemblies that you could fit up to the radiator? One thing I've seen here on lots of swaps, and on various other forums, is that the OEM fans are proven commodities, and that if you can find with dimensions that are close enough to make it work, you'll probably be better off going that way than trying to fabricate something on your own.

The0nlyon3

I have thought about going that route, especially since I found out I can control a brushless radiator fan motor with Holley Terminator X.

I wouldn’t know where to start as far as figuring out what factory shroud would fit my radiator. I have the dimensions for what I need but to my knowledge, there is no way of searching available factory shrouds by dimensions… it’s all application based and they typically don’t list the part’s dimensions..

for now, I’m going to fab up a shroud for some 12” fans and run them in line with each other (not staggered).

Novapat67

I'm using f body (99 Camaro) stock radiator and fans and am using a pwm controller from a ford fusion to control it via Holley terminator. Very slick setup. Doesn't get hot and I live in Arizona. If it were me, I would see if those fans would fit your radiator. If you want, send me a message and I can measure it up for you. Just an idea. They move a TON of air!

wave1957

Couldn't you go to a Pick'n Pull junkyard with all your dimensions, and measure fans on the cars?
After fitting an LQ9 in my '70 Impala, that is what I did, I have found a pair of fans from a '95 Chrysler Intrepid with the factory shroud that fits my rad (factory '70 Impala) pretty much exactly, and I have never had to think about my engine temp ever since (15 years ago). Cheap, too!