Here's my super-reliable combo, for your perusal;
>As for fan-clutches;
I run a HD Thermostatic fan that came from FORD, off an early 2000s pick-up truck. It keeps the coolant in the zone of 205>207, no matter what.
>As for the fan; I run that honking big, 7-blade, hi-attack angle, all-steel unit I think came off a Mopar A/C car .
>As for water speed, my system is underdriven, cuz it's a 4-speed, and the rpm is always up, unless it's idling.
>As for rad size, I run a 26" from a 73-Swinger, in the virgin slanty rad-support, with a shroud, and an expansion-tank.
>As for the Pump, I run a Milodon hi-flow, which is just an 8-vane with an anti-cavitation plate, and an oversize shaft, to support that heavy fan/clutch combo.
>as for a stat, I run a Milodon Hi-flow .
>and all molded hoses, with a restricted bypass, and the heater-core is the main bypass..
Now I gotta tell ya that I also run hypereutectic pistons, and with all those cooling tricks, I still had overheat issues, with the DC 292/509/108 cam.
Finally in desperation, I pulled the engine down, increased the skirt clearance to ~.004, and the top gap to .032, the second to .028, and left the oil-rings at .026 which is the KB spec for Street NA.
Badaboom, that cured it.
But Soon
that 292 cam was history, I just couldn't make it do all the things I wanted it to do; In it's place was a 270/276/110. and the CCP was now up to 195psi.
the following winter, I recut the decks for a pop-up of .007, to use 039 gaskets, for a Quench of .032, up from 028.
And
This engine, with OOTB Eddie heads, does not care about Idle-timing. In fact, I used to run this 270 combo'd unit in parades at 500rpm/5*advance to get down to 3.5mph, with a 3.09 low gear, and 3.55s........ with a slightly underdriven pump no less.
Why so retarded?
Well that's where I ended up with the 292 cam, trying to get my 367 cubed/750DP/3650pound car, to pull itself with a 4-speed, on the curb-idle screw, ...... without bucking. It was terrible and I pulled that cam. whereas the regular Idle-timing for that 292 combo was ~14.
That 292 cam gave way to the 270, and when that one dropped lobes, I replaced it with a 276/110, which has been in there since 2004.
Thru it all, the Clutched fan on the HD pump, has been doing it's job like a champ, with the 1973 26"rad in the unmodified Slanty core-support, with a nothing but an expansion tank for help. That rad is now over 50+ years old..............
Oh, the stat is a 195. lol.
I run the 195 stat now, cuz that is what it took to swell up the pistons to cure the piston-slap after warm-up, now that they are at .004@room-temperature. In retrospect, I could likely have left the pistons tighter, but since the block was already at the machine shop for additional decking; I wasn't taking any chances. What I'm suggesting is that the KB skirt spec of .0015>.0020, might have been fine; IDK.
The car
went 93 in the Eighth with the 230* cam, and idles along all day at 4mph maybe a lil less, puts up with repeated blasts to 7200, and used to, before overdrive, cruise at up to 65=3000rpm, for hours. With overdrive it has been as low as 65=1600, but eventually settled at 65= 2240, where it has been now, since ~2004. so,
I can't complain at how it turned out.
I'm not telling you that this is what you need to run.
I am telling; you that this is where I ended up, which is, a rock-solid cooling system. If I don't see steam coming from under the hood, I never look at the gauge anymore.
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As to Idle-timing;
You can't hardly give your engine too much idle timing. Mine likes 30 degrees or more. But just try to drive it like that with a manual trans.
At idle, for a street-car to be able to drive away, your transfer slots need to be set pretty close to the same exposure, no matter what the cam may be, in my case between the 292 and the 270. I and most others have found that, a slot exposure under the Primaries of about square to slightly taller than wide, will get you into the ballpark. Then, to set your idle-speed, you use Idle Timing and or, Idle-air bypass.
Once you have the transfers working, the engine won't much care about Idle-Timing, set it at whatever doesn't bang into gear (auto trans), or with a manual trans, at whatever gets you moving without stalling or, with a lightweight flywheel, keeps the engine ticking over half-decently smooth. But, if you want to idle in thru the front gate, with that lumpy big-cam sound, you are gonna have to retard the timing. With a manual-trans, more-timing just means you can't drive slow. The power pulses with typical auto-trans timing, are just too powerful, and riding the brake will just make her jumpy.
So, here's how I cured that.
I installed a dash-mounted, dial-back timing retard module, with a working range of 15 degrees. My normal Idle timing is 12>14 to satisfy the transfers. But to drive slow, I can retard, in my case, up to 9 degrees, getting it down to 5*. I use the 6 remaining degrees to advance the Cruise-timing which is normally about 54/55*. but the timing unit can make that, up to 61*, for fine-tuning fuel-economy .
and yes, my Power-timing is usually 34*, but I can add or subtract timing, as the situation might warrant, right from the driver's seat.
Again, I'm not telling you that you must have this tool. I'm just saying what a great tool it is, cuz, in most cases, you cannot make the factory distributor do what needs to be done.
Happy HotRodding