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The Anti Yam!
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22,680 Posts
Almost any 302 5.0 head will fit a 351w 5.8

Im gonna look in my books when I get home, see if I can come up with any info on them for you. Like weather they have A.I.R. ports in them, combustion chamber size, etc etc.
 

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Registered
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1,209 Posts
You'll probably have to get the heads bored for the larger 351 head bolts, but that's no big deal. If they're SVO, they might even already have the larger holes and the stepped washers, but I don't know. Also dunno if they're ported for EGR or Thermactor offhand.
 

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Ex Navy Nuke
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5,421 Posts
As far as the head bolt holes go all you have to do is drill them out to 1/2". They pretty much all come with 7/16" bolt holes so they can be used on 302's or can be drilled out to 1/2" for 351's. My Twisted Wedge heads came that way and I had to drill them out, I think it took me about 20 min to drill them all out(no big deal).
As far as will they work? yes. They(302 and 351) are the same except for the head bolt holes which is easily remedied. I'll see if I can find anything on them too. Did you call the guy and ask for the specs on them? (valve sizes, combustion chamber size, intake runner size, how many miles, ported or not, specs on valve springs, pedistal or stud mount rockers). If all the specs are what you're lookin for and they're a good price then go for it.
 

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Master Bater
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7,277 Posts
Discussion Starter #6
I have no idea if these are "what IM looking for" Rob. I dont know much about this stuff.
I saw them for sale for 300 bucks, and figured i would ask here if they are any good. I figured i could use them with the eldebrock upper and lower intakes, as well as the cam, that Crazed used a while back. Are these any better than the edelbrock heads that could accompany the rest of the stuff? Can I throw them on now, with the stock motor and have any gains? All this stuff is foriegn to me.
 

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Master Bater
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7,277 Posts
Discussion Starter #7 (Edited)
got this info from the seller,

they are stock gt40 heads out of the ford svo catalog
Intake valve: 1.84
Exhaust valve: 1.54
Combustion Chamber: 65.5 cc
they are not stud mounted rockers but ape makes a kit
for them
they have 2000 miles on them
 

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The Anti Yam!
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22,680 Posts
Ok plug, ya stumped me.

I looked in many of my books and cant find that part #

I think they are the GT-40 iron heads in the pre 93 performance catalog. I dont think they have the provisions for air injection or EGR
(EGR wont matter on a 5.8 becouse it gets it from the pass side exhaoust manifold)

In 93 a similar set of heads was used on the COBRA Mustang. But it had all the smog provisions.

Are you running the factory 5.8 intake?
 

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Master Bater
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7,277 Posts
Discussion Starter #9
yes, currently. My motor is currently stock, and prolly not long for this world. I "think" I have a head leak somewhere. I am burning coolant, and my exhaust smells "coolanty", and figured I could either swap these heads on now, or just save them for the rebuild. the stock motor has like 150K on, and just feels tired (could be the weight and 4D's tho?)
 

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Ex Navy Nuke
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5,421 Posts
One of my searches brought up a discussion on Corral.net and it said that these heads are in fact GT-40(not sure about P, X or any of those though) and were used on 93-95 Cobras. With the specs you listed on them they sound like a decent deal. They're not $1000 heads but they are better than your stock ones.
 

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The Anti Yam!
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22,680 Posts
Those heads will outflow E7TE's, but like I said, Im not sure about the Air injection pasages.

Do you have emmisions testing in your area?

The EFI 5.8 is unusual in that the intake is the choke point.
Those heads will do almost nothing for you with the factory intake. With an aftermarket unit you will see some gains from them. But understand almost any aftermarket head, GT-40, Trick flow, world, will give better results than thoes.

But on a low budget build, they could be just what the Dr ordered. Especialy if you can aford porting and larger valves.

Even stock, they should be rather tourqy.

I'll look in some more books tomorrow, plus somone else may be able to add more.

I have been told that you can get 93 Mustang COBRA GT-40 heads "remaned from Advance for $200.00+ (per head) But I dont know for sure if that is true. Same for the GT-40 "P" head.

And yes, I know my spelling sucks :toothless
 

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Yup, I'm fullsize....
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1,798 Posts
plug ugly said:
well, the other option would be
http://store.summitracing.com/default.asp?target=partdetail.asp&part=WRL-053030

I didnt know which would be better.

As an aside, is it worth doing any of the top end on a motor with 150K (it might be more, i havent looked for a while), or is that a waste of time.
Plug, I know nothing about the heads you are asking about in your first post in this thread, but the one you listed from Summit doesn't look too good of a deal to me. It's a stripped head, meaning no valves, springs and most other parts and costs $289 per head (not for the pair). If you are on a budget, I'm guessing you're looking at spending alot more $$$ to get those heads from Summit ready to use.

From summit:

Cylinder Head, Windsor Jr., Bare, 58cc Chamber, 180cc Intake Runner, Ford, 289/302/351W, Each

Just my $0.02
 

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Diesel Gynachologist
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11,535 Posts
plug ugly said:
As an aside, is it worth doing any of the top end on a motor with 150K (it might be more, i havent looked for a while), or is that a waste of time.
I would personally just do the whole thing at once. you would probably be ok with just replacing the gaskets but if your going all the way into it why not rebuild it? you say it kinda feels tired anyway and if its like mine its probably starting to leak from every seal on it. my opinon is why bother with rebuilding the top end and have to go back into it for something else later? I say do it all at once and be done with it.
 

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The Anti Yam!
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22,680 Posts
RLKBOB said:
One of my searches brought up a discussion on Corral.net and it said that these heads are in fact GT-40(not sure about P, X or any of those though) and were used on 93-95 Cobras.
They may be the heads used on the 93 Cobra, but the part #s are different.
There not P,Y or X heads, they pre date those heads. These are almost certainly the original SVO GT40 heads. IIRC they where originally designed to go on a 25th anniversary special edition car that never materialized. The heads were sold through the SVO catalog. Very very similar (possibly identical) GT40 heads where later used on 1993 Cobras.

plug ugly said:
As an aside, is it worth doing any of the top end on a motor with 150K (it might be more, i havent looked for a while), or is that a waste of time.
Mustang guys do it all the time.
If you really want new heads do this.
1. Do a cylinder bleed down test. This is much more accurate than a regular compression test.

2. Get an oil analysis done.

If the #s for both look good then you can proceed if you want to.
If the #s are bad, start building another engine.

Remember you will see almost no gains with the factory 5.8 intake manifold.



stangmata50l said:
Another thing that you may run into, Plug...is that when you rebuild the top end and put all those fresh new non-leaky gaskets in there, your going to start losing your lower seals.
This is true and not true.
If the rings are in good shape and the engine still has god compresion this wont happen.

If the rings are preaty worn then the extra power will couse blowby, bulding up crankcase presures faster than the PCV can cope with. The result, leaky seals.
 

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The Anti Yam!
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22,680 Posts
stangmata50l said:
True. I'm making the assumption between "150k miles" and "tired motor" that the rings arn't exactly sealing like they are new...therefore allowing the crankcase to pressurize. ;)
True dat yo!!!

.........What...Just trying to spice it up. :toothless

The main thing is to do the test's to see before hand.
Feeling tired and actualy being tired can be two diferant things.

But ya, at 150,000 miles you verry whell may have worn tired rings, and if thats the case building a new engine is a better idea.
 

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Master Bater
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7,277 Posts
Discussion Starter #17
well, not being one for wanting to do anything twice, Ill take ians advice and just start building a fresh motor. Im no longer than bachelor, so moola is tight.

I miss the days of free spending with no one to answer to.:cry
 

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Master Bater
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7,277 Posts
Discussion Starter #18
OK, I called ford today, and these are the heads off 93 cobras. So will these work for my motor? i do have emissions testing in California, so I need to keep them street legal. Wht all would I need to ensure is in/on these heads?
 

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The Anti Yam!
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22,680 Posts
plug ugly said:
OK, I called ford today, and these are the heads off 93 cobras. So will these work for my motor? i do have emissions testing in California, so I need to keep them street legal. Wht all would I need to ensure is in/on these heads?
93 Cobras where emmisions legal in California so the heads should be fine. If they are complete then you should be able to go ahead and slap them on. Everything should match up fine.

Just remember that your factory 5.8 intake is gonna be holding the performance back.
 

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Some assembly required!
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5,402 Posts
Gacknar said:
If you really want new heads do this.
1. Do a cylinder bleed down test. This is much more accurate than a regular compression test.

2. Get an oil analysis done.

If the #s for both look good then you can proceed if you want to.
If the #s are bad, start building another engine.
I'm kind of in the same boat as Plug with my motor and looking at the same options he is. My question is, I understand the leak down test but have no idea where one could get his oil analyzed. Also, how many miles into an oil change should I wait to get this done, I'm sure doing it on fresh oil would not be productive. I'm assuming that they are analyzing it for bearing material. Is this oil sample something that would need to be sent off or is it common enough I should be able to find somebody to do it locally?
 
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