72GoldOlds350

Hey Olds Fam!

Long story short, I need to update the cooling system on my ’72 Cutlass. Drivetrain is updated with new 9in rear, TH400, and I’m about to install a 350 SBO engine build by Mark that’s 434ci and dyno’d 530hp/580tq.

Suffice to say, my current cooling system probably won’t keep up as my stock 350 already overheats a bit (well, not literally, bout she gets HOT and I’m sure if I was not always aware of the coolant temps, it would.) My current cooling system is stock with stock direct-fan (no fan clutch), and it also does not have a fan cowl.

Thoughts:

I already purchased an OEM fan cowl to help direct the fans air, as I figured that was the biggest issue as the car sits right now. At minimum, I wanted to get a new fan and thermal fan-clutch system. This would be cheapest, and then I was going to see how the new engine ran like that.

If y’all think this won’t be enough, what would you recommend?

Fun71

What radiator do you have? Two row, three row? Does the car have AC?

oldcutlass

There are other things that can cause your engine to run warm. Too lean, timing not advanced enough, not enough air flow, bad cap...

72GoldOlds350

Three row. Non-AC car.

Well, I know airflow is not up to par with no fan-shroud and an old fan. Cap is fine. Since the new engine is going in soon, I'm going to install the shroud I have and get a new fan with thermal-clutch fan and go from there.

I appreciate the help fellas.

oddball

I'd recommend using a clutch - that can help the fan be a little quieter when full air isn't needed.
Also recommend switching to a 2 row 1" AL or a 4 row copper rad.

A/C really puts a burden on the cooling system, so you're already ahead.

Anyway, in reality, put the fan shroud on it and run what you've got. Make sure the fan is placed correctly inside the shroud with your water pump length and spacer length. The fan should be roughly 1/2 inside to just fully inside the round lip. All the way inside or outside the shroud and it won't help.

If you want the fan to be a little quieter sometimes, then add a clutch. It's easy. And just monitor temps to see if you actually need an upgraded rad for your setup - you may not.

coppercutlass

I have a wicked little 350 running high 11's. I run 2 14 inch electric fans , and a moroso electric water pump drive and a flow kooler water pump. Running the water pump off of the belt would probably be better but I drive this on the street and race it at the track. The radiator is a big 2 row be cool radiator. I dont run a thermostat. Some argue against it but i have driven this car during the snow season on 28 degree days and it warmed up just fine. Car has 3.90's and a 3500 stall so it cruises well over 3k rpm.

That's what keeps my car cool.

72GoldOlds350

Thank you for all the info and tips, everyone!

I'm going to get a new fan and thermal fan-clutch, install the fan shroud, and see how it all runs with the new engine installed.

If anything is still sub-par, I'll re-post any updates in this thread for more advice!

olds 307 and 403

That 4 blade factory fan moves a lot of air. Guys on the G body site saw a 30 degree drop on a 403 over the 5 blade clutch fan on a 85 Buick Regal and a 60 degree drop over a buggered flex fan on a 88 Cutlass. The shroud will help, I am also getting one. For my 403 based 424 ci stroker I plan on getting either the Autocity aluminum rad with two 1 1/8" cores or the Cold Case aluminum rad with two 1 1/4" cores. Both have original looking tanks and will no doubt cool much better.

72GoldOlds350

Interesting. I just hate how my current fan doesn't have any clutch...