Serious question for people with advanced auto knowledge...
 

I'm a car nut. I don't drive a Pinto as indicated in my signature, nor am I a newbie to modding cars.

Here's the problem:
I have a 1977 Ford F150 Ranger hiboy that's my off-road beast and is $8k into mods for that purpose. It's not a lot of money for a Porsche, which I also am a nut for and own, but for a 1977 Ford, that's a ton of dough. I can't get the cooling right after more than $1k dropped into it including a 2 row aftermarket radiator and a full coolant system flush and replacement of hoses and fluids.

The motor is a 351 Windsor OEM with no mods but a tuned carb. The exhaust is a custom 2.5" piped exhaust to provide the right backpressure the motor needs/wants. It's been leakdown and pressure-tested and is not great, but well within what I'd expect for a 34 year old motor. The truck has 85k miles on it now.

The truck can run fine on level ground, but I live at 8k feet in the mountains, and regularly drop 2.5k feet to take my kids boating while towing a small trailer/boat of 1000 lbs maybe. The truck struggles on hills even without it. It has a manual fuel pump and actually stalls because of vaporlock because it gets so hot.

I'm now looking at a 7 blade auxiliary cooling fan for the radiator bolted up to it rather than the stock 5 blade that runs 6" behind it, or should I say in addition to it. I also have a 30 degree cooler thermostat at 150 rather than the stock 180, but that just prolongs the time until a problem happens rather than solving it.

What other things have you hard-core modders done on vehicles like this?

It could be deposits or restrictions in the water channels in the block, especially if you've used non-distilled water in the coolant. Other than that, you could switch to some electric fans, mounted to the radiator. Also, adding an oil cooler will help. Dropping oil temps will drop water temps/overall engine temperature. Both of those parts are pretty universal, you'll just need a way to tap the oil cooler into the oil system of the engine. A sandwich plate is an option, or drilling the pan and fitting some AN fittings.

-Matt

I'd get a good flowing elec fan strapped to the rad and you should be fine, does the current set up shroud? They are kind of important....

Shroud is definately key in the older big engine compartments of those trucks since the airflow has a lot less restrictive places to flow in lieu of where it needs to cool the engine. I bet the water jackets are clogged or restricted as previously mentioned, but why even run a thermostat for a hardcore off road beast? It sounds like heating the block is not a problem, I would just remove it altogether.

I have had many hot rods and street legal race cars over the years and here's what i found helps:

-Larger rad which you have already
-hi flow thermostat with a 1/8" hole drilled in the flat stamped portion to help bleed air pockets
- flow cooler water pump(hi flow)
-proper fan shroud that covers the rad and fits close to the fan.
-bleed the air out of the cooling system
- check the total ignition timing. too much advance will cause high coolant temps and detonation.

Also have the idle mixture set. It sounds like the truck is lean at idle. You can also go down a couple sizes on the main jets because most carbs are set for sea level jetting.

my guess why you have low towing hp is that you installed taller that stock tires with the original rear end gears. this kills acceleration and towing power.

With living at altitude you need more compression than sea level and you need to spin the motor faster to get performance back. a mild cam and aluminum intake will help too.