429/460 Overheating Issue

[cycleguy55]

Originally Posted by Speedwaypj

Update - mod shroud to include 95% of radiator... seemed better....still temp creeps up to 230F, but if I set idle high (~ 2500) it will bring it down to around 210.....still pushing antifreeze out, about 1 1/2 qt. Radiator cap inline with output, high location...may need expansion tank to accommodate expansion when hot.
... 6 blade flex fan, good shroud - pulling fine - better than most production shrouds, mild upgrade on engine...(when I had head off, everything looked ok...no leaking gasket)

I guess I'll get an aux electric fan...and see what happens....yes there is a plate behind water pump.
still doesn't make sense to me.....

Any more Ideas?????

Temperatures still seem high.

What pulleys are you running - high flow or standard? CVF Racing, for example, lists the high flow water pump pulley as 5.4" OD (single groove, double groove is 5.2" OD), while the standard is 5.9".

Is your overflow tube connected to a coolant recovery tank? I can't tell from the video. Old school / original Cobras used expansion tanks, but coolant recovery systems became common / ubiquitous in the '60s and do a much better job of handling the normal expansion and contraction of coolant. Having said that, 1.5 quarts seems high to me - I would expect less than 1/2 that, probably more like a pint or so.

FWIW, I'm not a big fan of most flex fans - they seem to be designed to minimize HP loss, rather than designed to move sufficient air. The 'wide blade' versions (e.g. https://www.summitracing.com/int/par...1315/overview/ ) would move more air, though I don't know how much more.

Do you have an updated video or photo showing the new shroud? The shroud s/b designed so the fan is half in and half out of the opening with 1" clearance from the fan tips. https://www.flex-a-lite.com/blog/the...roud-position/