Chamber size on heads that fit on the 200?

[fordconvert]

I picked up another motor for parts to try and get my 66 running again. My 66 had a 66 or 65 head on it. The new one suposedly came out of a 67 or 68. It has a larger log that is flat on the top and sort of has a hex shape on the sides. No EGR or AIR fittings. It also has what appears to be larger chambers. The machine shop was going to clean them up enough to CC them to make sure that Im not going to loose too much compression. Anyone know what the chamber sizes are supposed to be? I measured the deck height and got 0.046. 8cc's seemed to fill the dish on the 60 over pistons. 9cc's overflowed but I didnt scrub all the carbon out first so Im guessin 9 is what its supposed to be.

My orignal head has questionable machine work with new guides that need replaced again and a few new seats. The newer head looks like it has never been touched but is a bit rusty so it will cost a bit more because it may need an intake seat or two.

At this point I dont want to do anything with the bottom end because compression was good and Im out of money and have not found a better block yet.

 

[80Stang]

Post the part numbers of the heads. That is on the log and starts with C or D...

 

[fordconvert]

I thought of that after I left the machine shop, I will call them in the morning and see if they can tell me what they are. How many options were there?

 

[CZLN6]

Howdy TJ:

Casting codes will give you the best estimation of what you have, but may not be definitive. The big generality is that all heads before 1970 were 52 ccs or less. The '69 "M" suffix heads were the 1st of the 62 cc chambered heads. The shapeand volume of the log, the increase in diameter of the carb hole to 1.75" and the larger chambers to reduce CR are the most significant features. This was also the 1st head to be used on both 200 and 250 engines. From 1970 on we can decern no difference between 200 and 250 heads.

Prior to 1969 there were some castings unique to engine sizes. The C0DE casting was only used on the 144 from 1960 - 62. The castings we've been able to measure ranged from 44 - 51 ccs.

The C1DE castings were unique to 170s. They measure from 48 - 53 ccs. The big difference between the 170 casting and the 144 was the increase in intake valve size from 1.46" to 1.52". Intake tract volume increased slightly.

There was a C4 casting that may have been unique to 170 engines. It had a more kidney bean shape to the chamber and was slightly smaller in cc. It had the same 1.649" intake valves as the C5 170 and 200 castings, but less volume in the log.

By the C5 castings valve and chamber size and intake volumes standardized- as much as FoMoCo quality control was capable of.

So, no matter what the casting codes are- measure volume for yourself to take the guess work out of your CR.

Stock '65 -66 piston dish volume is speced at 6.5 ccs. Report your deck clearance in inches. Typically a stock OEM '65 - 66 200 will measure about .025".

Keep us posted.

Adios, David

 

[fordconvert]

I didnt talk to the guy that did the work but the other guy in the shop said they came out 14cc differnt. I forgot to ask about the casting #s. With my strange bottom end I get 8.5 with the older smaller head and 7.25 with the larger one. Looks like I am going to have to go with the smaller one and hope I can come up with a good bottom to work with it at a later date. I started another topic asking about pistons.

I should have started this project in the winter when there was no pressure to get this thing back on the road.

 

[CZLN6]

Howdy TJ:

A difference of 13 ccs indicates to me that the smaller chambered head has already been milled as part of a previous rebuild or valve job. YOu will need to know the actual volume to accurately figure CR.

Regardless of which head you use have it milled enough to compensate for the thicker composite head gasket you'll be using and then another .030" to get the CR back to the stock range.

You'll be doing yourself a favor by specifying that the intake valves get and back cut, and the seats are cut to at least three angles.

YOu might consider having the shop bore out the carb hole to 1.75" too.

Adios, David

 

[fordconvert]

The newer head number starts with C9 and has 61cc chambers.

The older one has been cut down to 48 cc chambers and works out to 8.5:1 with my existing bottom end so thats what I am going to go with for now. It already has hardend exhaust seats and guides that are not too bad so it should be a fairly easy (and cheap i hope) clean up that will get me a few thousand miles while I keep an eye out for a good block to rebuild.