302 head help

[gwaii]

Here's a little bit of info. Doesn't mention any flow details.

A '96 Explorer came with GT40 heads. Look for the id right beside and right above the long bolt in my photo.

thank you very much

that's some excellent info,i see the explorer ones have a bigger combustion chamber than the cobra ones,that'll figure into piston choice regarding compression ratio.

it's a nice little increase on the valve sizes.

 

[fordmike1]

still curious though,should my 96 explorer have the gt40 heads?.i can' find any info on this in the tech section.also,what are the differences between these heads and the old regular smallblock heads?

Look at the passenger side head just behind the front head bolt and if front of the #1 spark plug you will see that it has GT cast into it.

GT=GT40
GTP=GT40P

 

[gwaii]

Look at the passenger side head just behind the front head bolt and if front of the #1 spark plug you will see that it has GT cast into it.

GT=GT40
GTP=GT40P

ya,i'll be checking that once some of the snow melts off the hood of the thing,i was just wondering if they also came with the standard heads or if you've got a v8 explorer then it's a given you've got the gt heads.

this info needs to find it's way into the tech section

 

[baddad457]

thank you very much

that's some excellent info,i see the explorer ones have a bigger combustion chamber than the cobra ones,that'll figure into piston choice regarding compression ratio.

it's a nice little increase on the valve sizes.

JFYI............The Cobra heads are the same castings as the other GT40 heads. But to reduce the combustion chambers, Ford had only the Cobra heads milled one more time versus the std GT40 heads...........something to consider if you have a set of these and want to mill em even more.

 

[gwaii]

JFYI............The Cobra heads are the same castings as the other GT40 heads. But to reduce the combustion chambers, Ford had only the Cobra heads milled one more time versus the std GT40 heads...........something to consider if you have a set of these and want to mill em even more.

cool....there's more info on these things in this thread than i've been able to find searching the whole site.

 

[shane96ranger]

Well that can be answered in many ways.
If you are wanting to use them as door stops then they both are the same.
If you are wanting them for a ranger V8 conversion then the GT40's are way better.
If you are wanting them for a Mustang for stop light to stop light performance the GT40P's are better.
If you want them for all out higher RPM performance in a race application then the GT40's would be a little better.
So to answer your question; Its all on what you are wanting them for as to which one is better.

Nicely said Mike! This is why I used P heads on my Mustang:

"If you are wanting them for a Mustang for stop light to stop light performance the GT40P's are better."

They were the best 225 dollar upgrade I've done yet. The only other kick in the pants that was comparable was gears, and I paid more to have the gears done.

 

[shane96ranger]

For anyone interested, here are some flow numbers of some stock and aftermarket heads. Compare the P's to the Windsor Jr's.

http://www.carbdford.com/tech/flowdata.htm

 

[Mac]

Head flow data but the standard GT-40 not listed.
Dave
http://www.carbdford.com/tech/flowdata.htm

 

[shane96ranger]

That's odd Dave, it used to be in there. I did the comparison between the two when I got mine using this exact chart. I wonder why they removed it? I remember they had a separate listing for the Cobra and Explorer GT40's.

 

[shane96ranger]

Here's another one that I've seen.

http://www.allfordmustangs.com/Detailed/630.shtml

The exhaust valve is smaller in the P heads, but because Ford changed the plug angle, the exhaust on the P's outflow regular GT40's.

BTW, I can't get the comparison button to work but the graphs show the numbers anyway.

 

[baddad457]

Here's another one that I've seen.

http://www.allfordmustangs.com/Detailed/630.shtml

The exhaust valve is smaller in the P heads, but because Ford changed the plug angle, the exhaust on the P's outflow regular GT40's.

BTW, I can't get the comparison button to work but the graphs show the numbers anyway.

Wasn't the plug angle that improved the flow, it was good old fashioned port work. The ports were redesigned vs the std GT40 heads. The plug angle was to move the electrode closer to the center of the chamber, same as with the E6SE heads. (only they didn't get the odd angle too) .................................If y'all are interested in the story with the GT40 heads, go look in Ford's "The Official Ford Mustang 5.0" by Al Kirschenbaum, published thru Ford Racing. Lots of good tech info in it on the 5.0 from 79 to 2001.(and not just the Stang motors)

 

[shane96ranger]

The ports were redesigned vs the std GT40 heads. The plug angle was to move the electrode closer to the center of the chamber

If you look at the port, moving the angle of the plug provided a more direct shot. I was comparing mine to my E7TE's side by side and you can clearly see this. The E7TE's have more of a kink in the port. Maybe I was wrong and Ford took some meat out of it, but it looked like the plug angle being moved provided more space. Should have taken pics I guess.

EDIT: In an attempt to find a pic, I see it is indeed Ford's handy port work that improved, and my eyes deceived me. Thanks for the correction BADDAD.

 

[gwaii]

well,i'm just happy that with the information in this thread i've confirmed that i have the gt40 heads.those markings are not easy to find on a fully assembled and running explorer,but once i knew where to look-there they were.

they are wasted on the explorer for it's intended use,but will be traded for regular ones and used on a slightly more high performance engine.does anyone have info on using these on a 351w.i'm assuming that the 302 still uses 7/16 head bolts,and will need reaming to 1/2'' for this swap.....anything else i might need to look for?

 

[shane96ranger]

well,i'm just happy that with the information in this thread i've confirmed that i have the gt40 heads.those markings are not easy to find on a fully assembled and running explorer,but once i knew where to look-there they were.

they are wasted on the explorer for it's intended use,but will be traded for regular ones and used on a slightly more high performance engine.does anyone have info on using these on a 351w.i'm assuming that the 302 still uses 7/16 head bolts,and will need reaming to 1/2'' for this swap.....anything else i might need to look for?

The Lightning 5.8 used GT-40 heads, which I'm sure were drilled to 1/2". It only made 240 hp though, but made 340 ft. lbs of torque. You could really wake up that Explorer with a cam.

 

[baddad457]

. You could really wake up that Explorer with a cam.

But only if the computer will handle it. I've heard that it has problems with bigger cams. A set of 1.7 full roller rockers will definately help. The Explorer cam is just a tad less cam than the HO's came with. The 1.7's put it on par with the HO cam. As for using the GT40's on a 351, the net result is about what the 69 351W 4 bbl motor was.