thoughts on what was done to these heads

[hurlbird]

so as not to confuse my other post regarding rocker arms. Enclosed are pictures of the heads in question. I think I need to get an idea of what was done to these heads before I pursue rocker arms now that I took the rockers off.
*1974 heads
* no 302 casting
* 22 on the front edge
* That other symbol seen in picture
* T and an I casting

Based on the pictures does anyone have an idea of what was done? Looks like they were performance improved. Also they had 2x valve cover gaskets to keep the rockers from striking the valve cover. Id like to leave them alone at this point. Thoughts on a more professional "thick' gasket idea?

[gt350hr]

  Check your casting numbers. I believe those are 84 heads NOT 74. In '74 press in studs were still being used.

[hurlbird]

hmmm. running 68 cobra intake and stock 68 exhaust manifolds. Would heads that new work/fit? I assumed someone drilled them and went through them. Julien date 4C31 i assumed 74... Block is too.

[gt350hr]

hmmm. running 68 cobra intake and stock 68 exhaust manifolds. Would heads that new work/fit? I assumed someone drilled them and went through them. Julien date 4C31 i assumed 74... Block is too.

Better check the actual casting numbers. You will probably get a surprise.

[Coralsnake]

I think you have to take the head off to check the numbers?

[68stangcjfb]

Those rockers started to be used around 1977 or so. The good news is you can buy 1.6 or 1.7 ratio rockers that fit 5.0 Mustangs.

[pbf777]

I think you have to take the head off to check the numbers?

     The actual casting numbers are located under the inlet port casting area viewable with the intake manifold removed and the use of a mirror and flashlight.  Casting date codes are under the valve covers.       

     Scott.

[hurlbird]

the block is D4DE-6015-AA dated 4F12 and the heads are 4C31. so I assume its all 1974. Not knowing a lot about heads I thought maybe someone who does might be able to spot the springs and rockers and give some hint as to what was done. The fact that someone took the time to make the studs screw in tells me some performance intent was made. I ordered the 5/16 valve cover gaskets hoping the rockers wont hit my COBRA covers.

[pbf777]

     Looks like stock type "styt".       

     And, I think I might agree:

  Check your casting numbers. I believe those are 84 heads NOT 74. In '74 press in studs were still being used.

     Scott.

[68stangcjfb]

Those are stock 80s heads. The Block & head casting dates are too far apart in my opinion to be Factory assembled. This is a picture of an 80s head. Notice they look exactly like the ones on your car right down to the yellow paint on the valve springs. The Cobra intake bolts right onto them with the right gaskets. The old exhaust manifolds bolt on to them too.

[hurlbird]

son of a gun!!! Better/worse than 68's? any advantages?

[TA Coupe]

Those heads are set up to use pedestal Mount rocker arms. You can look at Summit here to look at a bunch of different ones and see what you might like.

https://www.summitracing.com/search/engine-family/ford-small-block-windsor/engine-size/5-0l-302/make/ford/part-type/rocker-arms/rocker-arm-style/full-roller/rocker-arm-mounting-style/pedestal?N=rocker-arm-mounting-style%3apedestal


     Roy

[hurlbird]

thanks.... Any thoughts if these heads are any good? Chamber seems to be larger than 68's.

[shelbydoug]

thanks.... Any thoughts if these heads are any good? Chamber seems to be larger than 68's.

It depends on what you call good and how you determine that?


The stock exhaust ports on those heads are smaller then the 68 302 ports are. The flow numbers on the 68 302 heads are basically the same as the 289 4v heads of the era.

You don't get into better flow numbers stock until you get into the '90s "GT40" heads but they still are a far cry from the current aftermarket versions of something like the AFR185.

Those flow 296 on the intakes at only .500 lift.


The race ported C6FE GT40 heads done by Mondello or Valley, according to Randy are only in the 220 to 240 cfm range. For the era, those were considered "state of the art" but were limited by the castings themselves.

Stock, '60s iron heads intakes are in the 180 to 200cfm vicinity and the exhausts are something like 80.

So to answer your question, your heads are not comparable to current performance heads and really can't be upgraded in anyway to be because of the casting limitations.



If anything, they are comparable to an '85-6 Mustang GT 5.0 head at something around a 200hp output.

[hurlbird]

thanks, so similar performance as the 1968? I realize not a "performance" head and am not looking to get into that world. Just curious.