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The GT40P heads do not have Thermactor ports.

Just keep your eyes open for the right deal to come along. Don't let money burn a hole in your pocket. A good set of 289 heads will pop up. Sometimes when you least expect.
 

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Discussion Starter #62
Hi, what about C60E and C6AE?

Anything special or desirable about those heads? I can get those cheap but they would need full rebuild.
 

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SF, the C6 heads should have the smaller 54 cc chambers. If you can get them cheap, you can do a valvejob and add the bigger valves and clean out the exhausts and add hard seats. The early heads, with the bigger 1.94/1.60 valving, can support ~450hp. I'll help with part numbers if you need Is that enough ? LSG
 

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SF, the C6 heads should have the smaller 54 cc chambers. If you can get them cheap, you can do a valvejob and add the bigger valves and clean out the exhausts and add hard seats. The early heads, with the bigger 1.94/1.60 valving, can support ~450hp. I'll help with part numbers if you need Is that enough ? LSG
How would you compare those heads withe the stated improvements to a set of GT40 heads?
 

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Flade, the GT40 & GTP heads have the same 1.84 intake valve and 145cc port as the early 351W heads from 1969. If you left both heads alone, and ran them as Ford made them, the GT40 head will be sharply ahead of the C6. But if the C6 heads, ( 1.78 intake & 125cc ports ) are improved with the bigger valves & some porting, they can catch up and easily pass the GT. The smaller chamber is nice on a 289. But prepping the 289 head to this level requires a valvejob, hard exhaust seats, some grinding, and sixteen new valves. You could have seven or eight hundred dollars into the heads. If you are looking for quick & dirty, and the revised plug angle of the P heads doesn't hurt you, then the P heads are fine.


Anyone who is doing the GTP head swap should carefully set the 289 heads aside and then send them to me !


Knowing the header fitment issues that some have had, and because I really like the 54cc small chambers, the e 64-67 289 heads are my favorites. Also, having been employed at the machine shop, I know how the small valve heads can be upgraded, is was a popular choice for many years, before the GTPs were even thought of. LSG
 

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Flade, the GT40 & GTP heads have the same 1.84 intake valve and 145cc port as the early 351W heads from 1969. If you left both heads alone, and ran them as Ford made them, the GT40 head will be sharply ahead of the C6. But if the C6 heads, ( 1.78 intake & 125cc ports ) are improved with the bigger valves & some porting, they can catch up and easily pass the GT. The smaller chamber is nice on a 289. But prepping the 289 head to this level requires a valvejob, hard exhaust seats, some grinding, and sixteen new valves. You could have seven or eight hundred dollars into the heads. If you are looking for quick & dirty, and the revised plug angle of the P heads doesn't hurt you, then the P heads are fine.


Anyone who is doing the GTP head swap should carefully set the 289 heads aside and then send them to me !


Knowing the header fitment issues that some have had, and because I really like the 54cc small chambers, the e 64-67 289 heads are my favorites. Also, having been employed at the machine shop, I know how the small valve heads can be upgraded, is was a popular choice for many years, before the GTPs were even thought of. LSG
Given the choice, I'd look for some "pre C6" 289 heads before the castings were changed to accommodate Thermactor passages.
 

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Discussion Starter #69
I'll go look at the 66 heads. Apparently they were fully rebuilt and only driven for 100 miles. Then the owner decided he wanted more HP and is going with aluminum heads. They were just pulled off the engine a couple days ago and the machine shop that took them off looked them over and said they are all good. I think I can get them for a couple hundred. I'll see what they look like.
 

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Even without the installation of larger valves, port-matching of the exhaust is a great improvement. I'm curious, though, are you talking about one OE head and one AE head?
 

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Discussion Starter #71
Even without the installation of larger valves, port-matching of the exhaust is a great improvement. I'm curious, though, are you talking about one OE head and one AE head?
There was a pair of 0E and a pair of AE heads for sale but they would have needed everything done to them. They were sitting for years and all rusty, etc. I passed on those.

Now I'm going to look at some 1966 heads that apparently need nothing. I'm not sure of the casting number yet. That's all I was told. I would do the port matching if I get them.
 

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Discussion Starter #72
So I ended up picking up a set of C60E. Seller told me they were rebuilt and he only put 60 miles on them and changed his plans and went to aluminum. He seemed very trusting. Got them for $180.

To me they look really great. I’ll do the exhaust porting before putting them on.


Don’t even have to paint them lol.

Should be an improvement from my worn out D8 casting ones that I currently have.

Plus I can keep my headers.



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SF, you ARE going to check those heads out carefully before just running them, right ? It looks like some of the exhaust valve tips are chewed up. And why are we seeing rail rockers AND narrow slots in the heads ? Like this set of rockers was an incorrect addition at some point ? You'll want to be certain that the rails on the rockers don't hit the retainers & locks. LSG
 

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Discussion Starter #74
SF, you ARE going to check those heads out carefully before just running them, right ? It looks like some of the exhaust valve tips are chewed up. And why are we seeing rail rockers AND narrow slots in the heads ? Like this set of rockers was an incorrect addition at some point ? You'll want to be certain that the rails on the rockers don't hit the retainers & locks. LSG
Thanks for the info. Win some and loose some. I guess I should have done more homework and been less trusting before buying them.

Anyway, so the rail rocker arms are incorrect for sure? Plus everything else should probably be looked over by a professional.
 

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SF, I believe the rail rockers are incorrect, but we don't know for sure if that is going to cause you problems or not. What can happen sometimes when the rail rockers are on the shorter tip valves is that the rails can chew on the retainers or locks. It doesn't look like yours have done that. But we also don't know if the heads ran that way, or the guy just wanted to give you a set of rockers and grabbed the wrong ones. Do you have any other rockers ? Are you able to grind the rails on these ? If the rails were shortened a bit, and they didn't touch the retainer or valve locks, and everything is inline with the pushrod slots, it may be fine. And look @ the exhaust tips....are some gouged up, or is the light just reflecting on a small wear pattern ? It may not be as bad as it looks in the picture. LSG
 

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Discussion Starter #76
I don’t have other rockers. I can grind stuff if needed no problem.

If I end up using them I think I would change to the proper rockers to be safe. However, If the valve length changes between rail rockers and non-rail rockers then I would need to confirm which valves are in there.

What do you mean exactly about checking the exhaust tips? Like the edges of the valve face in the combustion chamber?
 

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Looks like the valves are correct for rail rocker arms, valve tips for non rail rockers don't clear the retainer by much. With that said, I don't think I'd use the rail rockers with slotted pushrod hole heads because the rail may align the pushrod so that it binds against the pushrod slot. You'll also need to verify pushrod length.
 

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Discussion Starter #78
So I could change the rockers and get shorter push rods? That would work?

Or drill out the push rod guide to a 1/2" hole? Kind of a dumb question but I"m curious.
 

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If you really want to use the rail rockers you could drill out the slots, just check the rocker arms for wear, you may end up needing new ones anyway. I have a set of rocker arms the valve stem tips actually wore a round depression in half of them.
 

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Discussion Starter #80
If you really want to use the rail rockers you could drill out the slots, just check the rocker arms for wear, you may end up needing new ones anyway. I have a set of rocker arms the valve stem tips actually wore a round depression in half of them.
Yeah I’d sooner get new rocker arms then drill it out.


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