How are your steam bleeds on the heads set up?

 

L92 heads only have front ports. Stock Ly6 steam pipe routed to NPT port on rad just below cap

 

Two things you can look for when you car is idling too high with a new carb:
1. I have received carbs where the linkage bar between the primary and secondaries was bent too short. So, when the primaries close all the way, it opened up the secondaries and vice versa.

2. Some aftermarket carbs come with holes drilled in the throttle blades for extra air to accommodate large duration camshafts. This extra air in a car that pulls good vacuum can cause a high or uncontrollable idle.

After that, look at your timing. Make sure that you do not have too much timing at idle. I find that most cars do the best with idle timing between 16 and 24 degrees. Excessive timing at idle as well as too little timing at idle can cause run-on after the ignition is off due to poor combustion.

 

I put the holley back on after letting the engine sit overnight. Much to my surprise, it still runs hot and diesels. Remember, the holley didn't do this before.

Pulled the plugs and they are still rich, but much cleaner than with the QF. Most of the insulator is white. Im just going to ditch the internally regulated pump for a FP+Regulator so I can positively eliminate fuel pressure from the list of issues.

 

I seriously doubt the carb has anything to do with it overheating. Fuel pressure has only a subtle effect on how the car runs. The only way it will seriously affect you is if it is so high it is pushing open the floats and overflowing the bowls (easy to spot) or so low it can't deliver enough fuel at full load.

You have had your cooling system open so many times that you need to look there for the overheating issues. Odds are you haven't gotten all the air out of the system. Jack up the front end of the car to get the radiator to the highest point then remove one of the steam vents until coolant comes out before capping it again. fill the radiator back up and repeat. make sure you have a working overflow bottle and good radiator cap then heat cycle the motor 3-4 times. That should work all the air out of the coolant system.

 

I wish it was something obvious. This thing started with a closed cooling system, carb swap. Nothing changed on cooling system when the heat up/diesel prob started.

I have a hole in thermo, I bleed it nose in the air, empty rad. Pulled steam vent pipe, filled thru water pump outlet until coolant comes out steam hole. Then let it equalize and refill over a couple hours until its equalized. Put pipe back on, repeat until its full up to WP oulet. Put upper hose on, top off rad, then run it in the driveway with cap off. Yes it has working overflow and good cap.

 

Post good pics of your engine bay and rad setup.

 

 

Also a picture that shows the backside of the radiator with the fan setup and hose routing.

 

Ill have to get that this evening.

 

I don't mean to sound rude so don't fake this wrong as you'd be surprised at how easy it is to miss.

Are your fans running the right direction?

 

Believe me, I try to check the stupid things first. Yes, they are pull fans and they are pulling.

 

Sounds like you put some time into it! Just to make sure I understand you with everything assembled fill it through the radiator with a steam vent cap off. Pulling hoses can drain the top of the head.

 

I run the truck WP, with the long outlet on top. So when my truck is nose in the air on jack stands, thats the highest point on the engine side. I fill thru there, then let it equalize with the radiator. Once its equalized, system still open, I put the upper hose on, put it back on the ground, then filled/equalized thru rad cap.

Head gaskets are in correctly.

 

Now that I can see the pictures I see what you mean. Was thinking the vette water pump.

I'm just guessing at this point. Are you losing any coolant? Possible head gasket leak?

Just how hot is it getting? Fan set points?

 

When I first saw the pics I thought this was an S10 swap. Why is your motor so close to your radiator in a full sized truck? This is creating poor airflow and certainly isn't helping your cooling issues.

From what I see I'm surprised this hasn't ALWAYS overheated

 

Not losing coolant, not ruling out headgasket. Leakdown test is on my list.

Fans at 175/190 runs at 190. Changed fans to 205/210 runs at 205. Prior to this issue, it ran at 175.

 

This is where the Early Classic Enterprises mounts place an LS in this swap.

 

That may be but that still doesn't make it right.

Can you get a better lit side shot showing the space between the motor and the rad?

 

Im not following you on this one. The efans have a shroud that directs flow thru the fan openings. The radiator doesnt know how close it is to the engine nor is the engine preventing air from moving through the radiator.

The fan shroud is about 6" at its thickest, plus another 4-6" on the accessory drive.