halfafish,

I can pass on my experience in Brisbane Australia where we have hot conditions over the summer. I have a 1965 AP6 Valiant and 1970 VF VIP Chrysler.

The AP6 has a mild slant 6 (9.9 comp, 264s cam, etc.) with stock auto trans and rear end and runs a 2 core radiator, tefba filter with magnet, 6 blade fan with no shroud and 180 deg thermostat.

The VIP is complete stock and original, with original engine auto trans and rear end and runs a 2 core radiator, 7 blade fan with no shroud 180 deg thermostat. It also has air/con so has the condenser in front of the radiator.

I got both radiators built by Greg at Fuel Tank and Radiator Services (www.ftrs.com.au). The guy is incredible at what he does! He recommended using a much more efficient core in it's construction compared to standard.

The results have been fantastic in all types of driving conditions (city, country, hot, cold, etc).

For the AP6, absolutely no overheating issues at all. Same with the VIP, however it can creep up a little in 100 deg F conditions with air/con on in peak hour traffic. I'll be looking into a shroud and possibly even a small push thermo if it actually becomes a problem.

In your case it really depends on what you want (every last bit of torque/HP) and what type of driving will the car be used for?

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Love cruising in a bare metal Val!

General thoughts:

Would you consider an electric fan? Or two small diagonally offset electric fans to provide more room?

Agressive Ted documented his slant 6 build, and seemed happy with the use of an electric fan. (I think he called his engine a "160 HP, high torque build")

The fan itself does not matter so much as it's ability to move air at lower vehicle speeds. So stop and go traffic jams in the summer, Towing a trailer, and city traffic demand more from the cooling system.. If you primarily drive on the open road, and above I think it is 25 MPH, the fan does not do much... Unless you have Air Conditioning...

Also doing a cooling system flush to get all rust and corrosion out of the block and head can do a lot for allowing the coolant absorb the heat that is being produced by the engine to actually transfer to the coolant.

Start reading here and click through to each next section.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Bare Metal Maz, thanks for the feedback. This car is a mild build intended for lots of torque on the street. I do not intend to race it.

Jase, I'm holding off on the electric fan idea, as the car will be a sleeper. The more it looks like stock the happier I will be.

SSD, thanks as always for the threads. I went through them all.

At this point since I have the ability to experiment, I think I'm going to try the factory unit with the Mercedes clutch fan and see what happens. It looks like a balanced approach, and if it's no good I can always stick the aluminum radiator back in it as I know it will not overheat with that one.