66 200ci and 81 250ci

[Anonymous]

I put an 81 250ci head on the 66 200ci on my wifes must. Wasn't looking for a performance boost, the orig 66 head was cracked and I had an 81 250 engine gathering dust. Car runs well but will overheat after running a long time. I used a 66 head gasket. I was wondering if anyone knows if I should have used an 81 250 head gasket or would need to modify the 66 gasket. The package on the 66 gasket says it's the same all the way up to 1980. Are the water jackets different, or should I look at something else being the problem, like maybe a clogged jacket somewhere?

Thanks,
Ben

 

[Anlushac11]

8)

The head gaskets and passages should be the same. Did you have the head milled?

 

[Anonymous]

Nope I didn't have the head milled. I know I probly should have, along with having it vat cleaned, seats ground, guides checked etc etc, but I was looking for a cheap way out.

If I was going to spend the money on the machine work I would have just gotton the 149.00 head at AZone instead. Which I will most likely end up doing anyway since this one doesnt seem to be working out right.

Like I said it just gets hot after running a long time. I drove it home yesterday evening and it didnt get hot untill about 20 miles into the trip and it sat at idle 20 min. b4 that. And it's not really overheating it's just runnin way on the right side of the guage. It'll blow out some with a 7lb cap on it when it stops runnin. But this is with the thermostat out. Only other thing is I have the heater core bypassed, I know that will make it a little warmer but not as much temp gain as i am seeing, I wouldnt think. Timing is set at 12degrees so I dont think its high enough for that to be makin it run hot, maybe i'm wrong on that one, any tips?

Other than this the car runs good now. I changed the head, lifters, Tchain set, oil pump, carb, fuel pump, water pump, pushrods, radiator and put a tune up set on it all in one pass. All that stuff was new xcept the head.

Anyone tried the Autozone head on thier 6? Have any luck with it? May order it next week and try it out if fundng permits. I've got my eye on a '63 falcon and if that deal doesnt go through I will buy the head. If I end up getting the falcon the new head will just have to wait a month or so.

 

[MustangSix]

Your choice of head should make no difference in operating temps. However, you should be running a higher pressure cap and a good thermostat.

First, make sure the radiator and the rest of the system is clean and not clogged.

Then spend the $9 or 10 bucks for a Stewart or Robertshaw thermostat. Running without a stat can cause cooling problems. The unrestricted flow lowers the operating pressure in the system and causes hot spots, esp in the exhaust port area.

Finally, look at getting a 13lb cap and coolant recovery system.