Head swap and overhaul.

[pookster]

Well I been looking to do a head swap on my 200. I done some research and figured out most of what to do, but I still have a few questions. I have heard that when swaping the head that often times after a few months it will blow out the rings and the best thing to do is overhaul the engine when you do the head swap. Now do I really need to overhaul my engine or will it be fine.
Second, I am a poor student so if I did the head swap I would have to wait a while before upgrading the carb. So could I run my carb that is has 1.5" hole on the later head with the 1.75" hole, so would it run ok or would it pose any problems.
thanks

 

[Alabama65stang]

Don't know for sure about the rings, but logic says you will have more compression and the potential for more blow by on the rings.

The carb is another issue. The bolt holes are farther apart with the later heads so you would have to make some kind of adapter to adapt the larger bolt pattern and venturi hole to the smaller carb.

 

[Anonymous]

Pookster;
Putting the 1978 & later head on the earlier engine will need some special attention or will WILL end up with LESS POWER and poor gas mileage as a result.

Here's what you MUST do, if you're only swapping the head: get a STEEL FORD HEAD GASKET or, at least, Ford's own composite gasket replacement unit. It's much thinner than the other aftermarket units, and it preserves the quench band height that you now have. Without that, you WILL suffer performance loss (been there ). If you can't find one of those, I have the Ford composite replacement for their steel units, which is just slightly thicker, about .007" to .008" thicker than the steel one (but still .010" to .025" thinner than the aftermarket types). Contact me then if you want one: I've got 2 left.

The other thing you MUST MEASURE and then adjust: the chamber volume in the new head. Your old head probably has smaller chambers than the later heads. So, you must mill the new head to get the compression ratio back. Typically, somewhere between .010" and .025" must be removed from the new head to make it about right - but you MUST MEASURE to get it right.

If you need further advice about how to do all this, drop me a PM.

MarkP.

 

[Anonymous]

or you can just get the head shaved

 

[pookster]

I know about the head shaving to get the correct cc's, but my question is will the swap cause my piston rings to blow later on?

 

[sreno]

Pookster,

I've done both. I changed the head to a 1980 model. Shaved the head, and IIRC it was about 40 tho. Been running a little over two years with no problems and have done nothing to the bottom end. I'm also using my original carb. I modified the adapater plate by elongating the bolt holes on the ears of the adapter. Its been running good also.

Good luck,

sreno

 

[Williboy]

I ran my Org Holley from the 144(1.5) on my '69 head (1.75) buy using the carb adapt from the 1.75.
I had to drill and bolt a throttle stud onto the side that I removed from the old base ontoo the new but it worked fine.

 

[MustangSix]

Pookster,

Taking your "poor student" comment to heart, the LAST thing you should do with limited resources is try to build just one part of the engine. Unless your old head is worn out and in need of a rebuild, a head swap on a tired engine with a stock cam and carb will yield almost nothing to gain for your time and money.

The idea behind swapping heads is to provide a base for other airflow improvements to work, and unless you do them in concert, the power yield is disappointing. A head swap affords the opportunity to do some porting, adjust the CR, get some bigger intake valves, maybe swap to another carb, add a cam.....but if cash is tight, you would be better served by other upgrades first.

Get a good Duraspark or 68-up distributor with a Pertronix. Upgrade the exhaust with a decent muffler. Maybe do something with the brakes and suspension. All of those will make the car better to drive, might improve economy, and can be done on a student budget, one step at a time.