200 head vs. 250 head

[colocounty4]

Hi! ok, I am truely a beginner at this so I need to lay some seriously elementary questions on you guys regarding the 200 to 250 head swap. I have a tired '65 200. I'm reading that I should consider swaping to a 250 head as I start working on the engine. As I understand it, you can benifit from larger valves and increased chamber volume.

1. Why can't I just put bigger valves in the 200 head?

2. As people discuss the increased volume, they turnaround and say you have to mill it down to compensate. Aren't you back to where you started with the 200 head?

3. Folks also say the carb hole is bigger. If you mill a 200 head flat, hog it out and put on a 2V does that matter anymore?

4. Harded seats. You can install those in a 200 head, right?

So, what am I missing? :| :help:

Seriously, I can change spark plugs and that's about it. I'm going to learn how to change points and adjust the timing soon. My Dad is coming up to show me. Then I'm going to figure out how to rebuild a carb. You're thinking I'm 16 and just starting out, right? :rolflmao: Nope, 42 and wanting to learn some new skills.

Thanks guys!

 

[rocklord]

Hi! ok, I am truely a beginner at this so I need to lay some seriously elementary questions on you guys regarding the 200 to 250 head swap. I have a tired '65 200. I'm reading that I should consider swaping to a 250 head as I start working on the engine. As I understand it, you can benifit from larger valves and increased chamber volume.

1. Why can't I just put bigger valves in the 200 head?

2. As people discuss the increased volume, they turnaround and say you have to mill it down to compensate. Aren't you back to where you started with the 200 head?

3. Folks also say the carb hole is bigger. If you mill a 200 head flat, hog it out and put on a 2V does that matter anymore?

4. Harded seats. You can install those in a 200 head, right?

So, what am I missing? :| :help:

Seriously, I can change spark plugs and that's about it. I'm going to learn how to change points and adjust the timing soon. My Dad is coming up to show me. Then I'm going to figure out how to rebuild a carb. You're thinking I'm 16 and just starting out, right? :rolflmao: Nope, 42 and wanting to learn some new skills.

Thanks guys!

Assuming you're asking why not just do all of the things to your 65 head as opposed to a later ('78 plus) head:

1. Yes you can install larger valves into your 65 head, but that would require your machinist to enlarge the openings. The later head already has larger openings.

2. The increased volume mentioned is referring to the log volume in the later head. The 65 head has a smaller log volume. Even if you directly mount a carb, you have a restriction to the outer cylinders; the later head would have less restriction to the outside cylinders (1 & 6). You're correct in that the later head has larger chamber volume and would have to be milled to get the compression ratio back up, but you probably have to have the 65 head milled flat anyway. So it would take the machinist a couple more swipes in the milling machine, wouldn't cost that much more.

3. Same reason as #2.

4. Same reason as #1. Why have it done to an early head for additional $$, when it's already done on a later head.

If you've read any of the posts in great detail, you would have noticed the recommendation to purchase the Falcon Performance Handbook. This book would answer a lot of your questions.

Welcome to the forum, and have fun!

 

[rbohm]

Hi! ok, I am truely a beginner at this so I need to lay some seriously elementary questions on you guys regarding the 200 to 250 head swap. I have a tired '65 200. I'm reading that I should consider swaping to a 250 head as I start working on the engine. As I understand it, you can benifit from larger valves and increased chamber volume.

you should consider going to the later 200 or the 250 head for the increased volume in the log.

1. Why can't I just put bigger valves in the 200 head?

you can put larger valves in the older head with no problem. in fact i always recommend doing just that. a 1.75in/1.50ex valve will help the breathing of the stock head.

2. As people discuss the increased volume, they turnaround and say you have to mill it down to compensate. Aren't you back to where you started with the 200 head?

increased volume in the log, and increased chamber volume are two different things. you want small combustion chambers, and large log volume.

3. Folks also say the carb hole is bigger. If you mill a 200 head flat, hog it out and put on a 2V does that matter anymore?

nope.

4. Harded seats. You can install those in a 200 head, right?

yes you can install hardened valve seats in the early head with no problem, but you dont need to these days as a lubricant has been added to the fuel mixture to replace the lead that was removed many years ago. that and valve recession is not the problem it was once thought to be. so save your money and dont worry about running hardened seats.

So, what am I missing? :| :help:

money?

Seriously, I can change spark plugs and that's about it. I'm going to learn how to change points and adjust the timing soon. My Dad is coming up to show me. Then I'm going to figure out how to rebuild a carb. You're thinking I'm 16 and just starting out, right? :rolflmao: Nope, 42 and wanting to learn some new skills.

Thanks guys!

check out the september 2009 issue of mustang monthly. they have an article on rebuilding the 200 from 1965.

 

[CZLN6]

Howdy Back Colocountry:

And welcome to The Forum. In addition to the info already posted to your questions let me add;
*for all practical purposes, the 200 and the 250 heads are identical given the same casting code. The only exception is a C9xx M suffix head. It was first used in 1969 on the brand new 250 engines.
*all heads after 1975 (D7xx and later casting codes) will have the larger volume intake log, 1.75" intakes and hardened valve seats. Chamber volume is now 62 ccs as opposed to 52 ccs on earlier heads.
*the exhaust manifold mounting ears are more heavily cast to be less likely to break off.
*what ever head you use you'll likely have to mill because OEM type steel shim head gaskets are no longer available. Modern replacements ar .020" to .030" thicker.

Is your engine factory original?

Again,Welcome and keeep the questions coming.

Adios, David

 

[colocounty4]

Hi,

the engine is original. I would like to keep it. The head is not original, it's a warranty replacement that was installed in late 66 or 67. Dad forgets which. I would have no problem swapping heads as long as they looked basically the same externally.

 

[rbohm]

8) for those of you wanting the early styel steel shim head gaskets, check with these guys, the last time i asked they had them;

http://egge.com/