[DOCTOR DC]

lets just say I disagree and think that a shroud will be the best thing for the mans car, in my opinion.

[55effie]

I plan on keeping most of the truck usable as I can, which means I want to use the heater and such, want to keep the stat for quick warm ups, and so on and so on. Yes, I meant .090 on the thickness.

I dont sweat the temp until is cranks up around 200 degrees. Then I worry. It seems to cool fine once I am moving, but the idle at stop and VERY SLOW creeping traffic just kills the stupid thing. It boils over faster than oil prices in the gulf.

1) So, if I go with the mech fan and shroud, what depth should the shroud be in the least? Right now it is at 2.5" depth before I make the blade tunnel. If I need more, I can move the fan closer to the block and cut down the spacer that the fan is mounted to, thus adding more depth to the shroud.

2) However, and electric pull fan is looking more and more promising right now due to low cost and efficiancy. They just look lame to me, like an afterthought.

3) Last, what is a good operating temp for a naturally asperated 383 stroker with a 625 CFm carb on it? It seems to hover around 170, which seems low to me.

[red65mustang]

again,
"if" just pinching off the heater hose test for more rad flow at idle does dramatically slow down (likely) or stop the temp climb at a light then mount a $6? on/off valve something like this pic attached....

when fall gets here,,,just turn the valve to open so the heater works...

"block off the heater" was a bad choice of words....
......................

shroud:

there are no hard/fast demensions rules because various fan blade's pitch and shapes (air blow direction) vary so darn much....
ex???:
on my wife's stock jimmy the front edge of the plastic 10? blades fan is about a full 3.5" from the fin's surface of the rad and has a full 2/3rd's of the blades within the (5" approx deep overall) shroud....

my mustang 5 blade's fan is fairly close to the stock spacing position and the blade's front edge is only about 1 inch from the rad fin's (with 2/3rds in my custom made 3.5" deep shroud)

the pitch and blades demension's are similar on both those fans...

either configuration does make/force the fan blade's to pull virtually 100% of the air only thru the rad at a traffic light which is the goal of the shroud....
...............................

just a comment...

the 170 at cruise is likely due to to much air moved by the direct drive fan at cruise rpms "and" ALOT more cool air coming into the engine compartment over the rad support and other front openings...

and/or there is likely a 160* (high flow?) degree stat in the motor???

LOL,,,be happy!!!
running too cool is easier to correct than too hot...

[55effie]

Originally Posted by red65mustang

the 170 at cruise is likely due to to much air moved by the direct drive fan at cruise rpms "and" ALOT more cool air coming into the engine compartment over the rad support and other front openings...

I would rather have it operate at 180-190 more consistently, but not blazing hot at traffic lights.

The bypass idea is something that I will look into.

Originally Posted by techinspector1

Not thick enough. You need more depth front to rear to allow the fan to pull air from the entire area of the core, not just in the middle of the core.

That is the main shroud. I have a 1.75 ring to add as well for the fan to sit into, with 2/3 of the fan in the ring. It places the fan about 3.75" from the radiator. I dont think that is too far away with my shroud design.

[FASTFORD]

since the temp rises at a stop light/idling, the problem is definitely air flow.
the shroud should "cure" the problem. if the new shroud only partly helps, then I recommend another radiator for this application since it was made for a 6 cylinder.
a high performance motor usually needs a bigger/better cooling system than the factory set up to operate effectively.

[49willard]

I have a 49 F-1 set up with a 383. You are ahead of me. I am still a ways from a driver. I did two things to improve cooling since I am setting it up to tow up to 5000#. First I installed a Zips waterpump risor. It centers the engine driven fan (with a clutch) in the radiator. It raises the centerline of the fan on a sbc almost 5 inches. I then custom made a ss shroud using two large steam table pans and some ss sheet stock. I also am running the largest diameter fan that I could fit. This is a link to pix on the FTE website which you should join if you are not already a member. http://www.ford-trucks.com/user_gall...&albumid=27774

[55effie]

You are the second one on here to recommend a water pump risor. I think that might be something that I do in the future. What kind of build are you doing to the 383? I love mine, but it is a bit much for a truck. It breaks loose way too easily. One day, down the road in a far off land of unlimited funds, I will link it and put it on air bags. But that is down the road, the yellow brick road right now anyway.

I know of a complete 49 F-1 here in the Springs where I live if you are looking for a good donor vehicle. I dont think it runs, but it is all there. I drooled all over it in the yard where I found it, but I have two other project vehicles right now, and dont need another one just yet .

[49willard]

Originally Posted by 55effie

You are the second one on here to recommend a water pump risor. I think that might be something that I do in the future. What kind of build are you doing to the 383? I love mine, but it is a bit much for a truck. It breaks loose way too easily.
I know of a complete 49 F-1 here in the Springs where I live if you are looking for a good donor vehicle. I dont think it runs, but it is all there. I drooled all over it in the yard where I found it, but I have two other project vehicles right now, and dont need another one just yet .

I built my 383 along the lines of GM's 383HT since as I indicated above, I want to tow up to 5000# and towing is all about torque. I did not want a screamer but rather low end grunt. My compression is just a little higher (9.5 vs. 9.1) than the 383HT and the cam has just a little bit more duration. It is set up with Vortec heads.
Thanks for the heads up about the 49 F-1 in your area. I am in good shape having owned my 49 since 1977 which I bought in Ca.

[55effie]

I asked because I need to find a tow rig, and since the mid 80s Chevs are still everywhere and are still a dime a dozen I am thinking of finding one and building up the 350 to the 383 for the same thing as you: towing and work only. With the diesel craze everywhere, a cheap gas engine now sounds more affordable.
I sold off a mid 90s Chev truck because it was bleeding me dry. One month it was a radiator, the next an alternator, the following month the ABS control module. It was like the 200K mark was actually the expiration date on the stupid thing. Once 200K hit, it just gave up.....and I took good care of the truck and never abused it. Cant say the same for the previous owner I guess. That is why I am thinking of going back to something more antiquated and lacks all the computer crap.

[aisr]

I agree that a shroud is an important part of an efficient cooling system, but sometimes you can get by with a less efficient system if everything else is mostly right.

Here's a common contributing problem i see is when an aftermarket distributor is used. Out of the box, they usually have the heavier springs and a small limit bushing installed...set up from the factory with a conservative long advance curve that comes in at higher rpm. The net result is that ign timing at idle is usually very low. With low compression and low idle timing, there is a good chance that much of the charge mixture is still burning after the exhaust valve opens as it flows out the pipe. This results in high exhaust and engine compartment temps, and more combustion heat transferred to the coolant by the burning exhaust in the ports. Higher underhood temps and more heat transferred to the coolant places more demand on the radiator. An engine with this setup would probably need a shroud even in a cooler climate.

With a long curve and stiff springs scenario above, you may only have 4 to 8 degrees at idle. For a hotrod engine, i usually like to see 16-20 degrees of advance at idle. It's easy to check with a timing lite and an accurate timing mark.
...If your distributor has vacuum advance, make sure it's connected to a manifold vacuum source instead of the smog era ported vacuum. Switching from a ported to manifold vacuum source can have a dramatic effect on coolant temp.
...If your distributor only has mech advance, switching to a larger limit bushing and lighter springs may be required.

[Daytona F1]

In the Ford F1's the top section of the radiator is up under the nose of the hood. The original design was for a vent in the front of the hood. If yours has been modified and that hole closed off, as mine has, the upper portion of the radiator is getting no direct air flow.

I have the same problem as you and am trying to find a shroud that will locate my 16-inch fan in the top portion of the radiator rather than centered. That will also solve my problem of clearance between the radiator and the pulley on the engine. You can't move the radiator forward or the bottom will not clear the lower valance.

[55effie]

I forgot to post some pics of the finished product. Here it is. Not quite what I wanted, but it seems to be working well. I cut and shaped the thing and paid a pro to weld it up for me. $25.00 for sheet of aluminum. $110 in welding. Making your own shroud? Satisfying to say the least. Two questions though.

1) I run a 180 degree T-stat. Is that too cold?
2) After final welding, the thing warped the front a little and pushed the shroud deeper into the engine bay than I planned, thus causing the fan to be completely engulfed by the tunnel. Is there any particular reason that the fan should be sticking out about halfway from the shroud tunnel as most people suggested? It seems to cool fine so.......?