I have a 63 f100 with a 77 7.5L (460BB) from a Linconln Mark V. In the summer the temp gauge got up to 200-210 in traffic and highway use. So I know the sensor does work. But now in the winter it only gets to 180. I blocked the radiator with cardboard and it helped a little but not anywhere close to 200+.

Last night I put in a 195 thermostat and drove it around but that didnt really help, it just got to 180 a little faster. Once I parked the truck I did hear some coolant come out of the radiator cap, and saw drip marks once I opened the hood and the overflow hose was wet inside(it doesnt have a overflow container yet, will install one soon)

It has a clutched fan on it which does spin (with the motor off) so I assume the clutch is working properly.

Any help to get this thing to proper operating temp?

I posted this in the 61-66 trucks but I forgot FTE had a 385 Big Block Section

 

Usually this is a symptom of a sticky thermostat, but since you are on your second one it's unlikely (but not impossible). Your overflow is functioning so you are eventually getting heat in the engine.

Out of curiosity, where is your temp sender located? Is this an aftermarket gauge?

 

The upper rad hose gets hot, so I figured the tstat is opening up.

The overflow hose was wet on the inside so that seems to be functioning, Ill have to double check by adding a catch can of sorts,

The rad cap leaked after I shut it off which is the first time it happened, I thought it would all go out the over flow hose.

The temp sensor is aftermarket since it was a motor swap. I cant remember where it was, I want to say it was in the radiator. Ill double check tonight and update.

...but in the summer it got to temp (200-210) so Im hesitant to say that the temp gauge is working but off and the 180 mark is actually 195. Because in that case 200-205 would be 215-225 and wouldnt that be too hot and cause the head to warp? Which I dont believe it has since the oil was clean during its last change, and it hasnt been running any different (no smoke from the tail pipe etc)

 

My opinion 210 is too hot, really no reason to run it that warm. Especially if you have water boiling over out of the cap. The upper hose gets hot when the thermostat opens-opening the flow of coolant to the radiator. Sounds like the cooking system is working fine, except maybe your radiator is partly plugged since you're getting hot in the summer. Do you have a mechanical temp gauge? If so maybe it's being affected by the ambient air temp. What is the reason for your concern? Will the cab not get warm, or do you just not like the number on the gauge?

 

You can use a laser thermometer to double check your gauge readings. Temp readings in the radiator will be inconsistent as antifreeze flows through and cools. Temps will be more consistent and should more closely match the thermostat rating nearer the thermostat housing. The factory sender location on a 460 is in the top of the intake behind the housing. The manifold in the pic is an Edelbrock, but factory is similar.

Overflow should go through the hose. Sounds like a new cap is in order.