E7s or GT40 ?

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E7s or GT40 ?

November 08, 2014, 12:54:14 AM

I talked to a buddy of mine about helping me with my HO conversion swap on my 87 Tbird and he told me 2 things.... (1) Im wasteing my time with E7 heads which I already had and should get a set of Explorer heads.....(2) I should switch to mass air. Im not looking for huge H.P. gains but just a fun weekend driver. I already have a stock GT cam and headers. What do you guys think?

E7s or GT40 ?

Reply #1 – November 08, 2014, 01:22:39 AM

GT40 all the way. MUCH better head. Unless you have money put into the E7 heads from a machine shop, I'd go GT40 instead. I don't recommend GT40P heads. Ran them, ran no better than the GT40's I switched from. Fuel economy and everything remained exactly the same, but now I had an annoying spark plug angle.

Both speed-density and mass-air should work fine with those heads. Mass air is a simple conversion, but still more work and money involved.

What are you doing for intake? HO upper? gt40?

E7s or GT40 ?

Reply #2 – November 08, 2014, 06:17:54 AM

I have an Explorer intake. What year Explorer head will I need? I would like to stay speed density but my buddy said with the labor involved I should do mass air. I know I wont be going to larger cams so Im thinkin SD is the way to go.

E7s or GT40 ?

Reply #3 – November 08, 2014, 08:29:32 AM

This shouldn't even be a question. GT40, Explorer intake, HO cam, headers. At that point you're flirting with the limits of 19# injectors, so go 24, and for THAT, you want MAF. I recommend fiveology racing's kit.
For heads and intake, your donor should be a 1996 or early build 1997 Explorer. P heads (late 97 to 01) will squeeze out a little more, but the extra isn't worth the pain. If you're fine with the limit placed on the motor by the 19# injectors, then stay speed density, you can always do it later. The combo at 16 deg BTDC is worth about 295 HP, the injectors will be maxed out around 300.

E7s or GT40 ?

Reply #4 – November 08, 2014, 10:39:08 AM

GT40/GT40Ps all the way. The E7s suck. Don't waste your time with them. GT40/GT40P heads are the best factory Windsor head casting. They are not as good as aftermarket aluminum heads but still decent. I swapped from GT40P heads to Edelbrock Performer heads and picked up ~50hp with no other changes to my combo. Edelbrock Performer heads aren't even the best flowing aftermarket head either.

E7s or GT40 ?

Reply #5 – November 08, 2014, 10:41:25 AM

I found a set of GT40P heads for 200$ ? Not sure of difference in P heads and GT40?

E7s or GT40 ?

Reply #6 – November 08, 2014, 10:44:51 AM

Quote from: ISTLCRUZ;440312

I found a set of GT40P heads for 200$ ? Not sure of difference in P heads and GT40?

They flow about the same. GT40P heads need special headers due to the way the spark plug is angled on them vs every other Windsor head ever made.

E7s or GT40 ?

Reply #7 – November 08, 2014, 10:59:25 AM

Quote from: ISTLCRUZ;440312

I found a set of GT40P heads for 200$ ? Not sure of difference in P heads and GT40?

Also note that the gt40p heads will most likely have smaller combustion chambers/higher compression. Not much, but a small boost over gt40.

gt40p heads will work, but the spark plug angle can make plug removal a c, even WITH the FMS gt40p-specific headers. I ended up loosening the FMS headers to remove two or three of my spark plugs when I had p-heads. I'd still run them over e7 heads.

E7s or GT40 ?

Reply #8 – November 08, 2014, 01:13:01 PM

I wouldn't worry about mass air unless you go 24# injectors like was already stated. specially if your running stock h.o. camshaft. Bone stock mass air vs speed density, the sd car is faster and runs harder.

E7s or GT40 ?

Reply #9 – November 08, 2014, 01:31:43 PM

Quote from: Seek;440316

Also note that the gt40p heads will most likely have smaller combustion chambers/higher compression. Not much, but a small boost over gt40.

gt40p heads will work, but the spark plug angle can make plug removal a c, even WITH the FMS gt40p-specific headers. I ended up loosening the FMS headers to remove two or three of my spark plugs when I had p-heads. I'd still run them over e7 heads.

I never had to do that with the GT40Ps and FRPP headers. I just used a box end wrench on the spark plug socket instead of a ratchet. Worked fine.

E7s or GT40 ?

Reply #10 – November 08, 2014, 04:02:23 PM

Quote from: thunderjet302;440318

I never had to do that with the GT40Ps and FRPP headers. I just used a box end wrench on the spark plug socket instead of a ratchet. Worked fine.

No spark socket would fit on a few of mine. I could get 5 out easily, 2 with some work , and 1 I could never get out no matter how hard I tried, until I removed the header. No spark plug socket would fit, without ratchet, and I have a few of various lengths. This was with the natural stainless FMS gt40p specific headers. Maybe I just have a slightly off tube...

E7s or GT40 ?

Reply #11 – November 08, 2014, 09:41:49 PM

I wouldn't mess with the E7's if I had to do it over again. A fun weekend driver is a very gray description. I would either come up with an e.t./mph goal or find a car that runs as you would like it and copy that combo. I'm finding out the hard way that it's cheaper to do it once right than fix it twice. GT-40/Gt-40p/best you can afford.
Check out this guy. His combo started out where you will probably be and is now at 329rwhp with untouched GT40p's and an Explorer intake. He's also mass air and tuned with Moates Quarter horse. I think both moates and tweecer both rely on having mass air just in case you want to dabble in tuning. Something else to think about.
https://www.youtube.com/watch?v=EnG8Sc3BUAQ

E7s or GT40 ?

Reply #12 – November 09, 2014, 06:11:36 AM

I have decided to go with the GT40 heads. I will have to put the build off for awhile until I get the heads and new headers.( I have stock headers and don't think they will work).....I don't want to use E7s an always wonder what if?........ Back to the drawing board. lol

E7s or GT40 ?

Reply #13 – November 09, 2014, 08:45:17 AM

When I built mine with GT40P heads, I used the BBK 1515 shorty headers, these work well but there's still an issue with I believe either number 6 or number 7 plug. I haven't tried the shorter style plugs as of yet but I'd think they would be better in those two cylinders. Also you will want a set of wires with 90° boots for the sparkplug ends due to header clearance.

E7s or GT40 ?

Reply #14 – November 09, 2014, 12:21:21 PM

Quote from: ISTLCRUZ;440352

I have decided to go with the GT40 heads. I will have to put the build off for awhile until I get the heads and new headers.( I have stock headers and don't think they will work).....I don't want to use E7s an always wonder what if?........ Back to the drawing board. lol

GT40, any headers will fit the same. GT40p, you should use special headers. The GT40p heads came with the smallest combustion chamber volume. Mustang Cobra gt40 came in the middle of the range, and other gt40 heads came with the largest. If I remember correctly, they average 58cc, 62cc, and 64cc. I also think I remember local shops charging around $40/head to mill them down a bit. I believe E7 heads average around 62cc. All of these values are around +/- 2cc due to loose manufacturing tolerances.