should I switch the 250 and 200 heads?

[Anonymous]

This is an emergency.
I have to make a decision Friday or Saturday about engines.

I just got a 1979 Fairmont with 200, C4, A/C. Nice car but the “bad head gasket" turned out to be a crack in the head, inside number 5 cylinder, from the intake valve to the left side of the engine (away from the spark plug).

I found a 1978 Fairmont 200 head at the auto salvage for $65. It is the only one I can find.

I also have a 1972 Mustang 250 engine. block: D2DE 6015-AA
head: D3DE 80?0-AA

QUESTION: Can I put the 1972 250 head on the 1979 Fairmont 200 engine, and the 1978 200 head on the 250 engine?

Why? you ask.
Because someone can use the Fairmont for their 16 year old to drive, and I will have the basic engine parts, for future installation into my 1965 Falcon sedan delivery which now has a 1969 200 with a 1971 Maverick 3.03 three speed.

Am I crazy for doing this switching, or am I smart?
I really appreciate your advice.

Charles in Illinois
1965 Falcon sedan delivery
1979 Fairmont Futura

 

[Anonymous]

The 250 head will bolt onto the 200 with no problems but you should mill the head ~ .030 to make up for the newer thicker head gasket .

 

[Anonymous]

200 and 250 heads of the same year are identical i believe. the only thing i would look at is chamber volume and valve size. I would keep the 78 head for my personal use as i believe (don't have my Falcon 6 Performance Handbook with me right now) it has the larger intake valves. Put the older head on the vehicle that would be leaving. And as noted head milling would be addressed on an individual basis as necessary to get the best out of the block it is going on.

 

[CZLN6]

HOwdy Charlie:

THe heads are virtually identical with the exception of 1.69" intake valves in the 250. Both will have 62 cc chambers, a 1.75" carb hole. The '72 casting may or may not have induction hardened exhaust valve seats. The '78 will have hard seats in both intake and exhaust.

Both heads will need to be milled to compensate for the composite type head gasket you'll use, replacing the OE thinner steel shim gasket. Read the Head Swapping sticky at the top of this forum for details.

Adios, David