GT40P Swap Information

[MustangShane]

I would like to get a thread started on GT40P (aka P heads) head swap information, and what works. The P heads offer a great junk yard upgrade to your 5.0 Mustang or 5.0 Swap into a Ranger, Focus, etc. The P heads were offered on 5.0 Explorers and Mountaineers starting during the 97 production year, and continued through 2001 when the 5.0 was discontinued. The P heads have a unique spark plug angle, unlike any other head. This limits your options for headers, but many people have found ways to get around it. As a side note, Ford Racing and MAC offer P-specific headers, but they are costly in comparison to other headers.

When I started my swap, I knew that I may be getting new headers to complete the swap. I had some old school MAC headers with the 4 piece flange - which I hate because you have to get a pry bar to get the holes to line up. So, I was OK with getting a different set of headers. BUT, they fit. I was able to use them by getting a shorty plug for cylinder 7. This bothered me, and I started looking for an alternative. I found a Brentech (Brothers Performance house brand) header on sale at Christmas 2 years ago for $109.00 - BINGO. I looked at the design, and could tell by sight that cylinder 7 provided more room.

NEW INFO! - Here are some flow numbers between the heads: http://www.carbdford.com/tech/flowdata.htm

Look at the difference in the room on cylinder 7 (2nd from right).

Here is cylinder 7 now:

You may see that my plug wires are not your usual 135 degree boot that the factory plug wires come with. I went to a 90 degree boot for some added clearance. The plug wires I used are for an 89 Chevy Blazer with a 350. They turned out great.

This is the passenger side. I had zero issues over here with either header. You can see there is plenty of clearance here.

OK, next issue. The P heads do not have the smog holes on the back like the factory E7TE heads. So, the tube that goes on the back side of the head is worthless. Don't fear if you have to pass the sniffer. Mine passed better with these heads. So now you will have the valve that redirects the smog pump to the back of the heads with no place to go. What I did was simply put a "T" in here that I had laying around.

If you look, the cap says "Antifreeze Coolant" on it.

Next up, I'd like to talk about the throttle body. The Explorer with the 5.0 has a 65mm throttle body. The factory Mustang throttle body is anywhere between 58mm and 60mm - mine measured at 59mm. The Explorer throttle body can be made to work using some parts from your factory Mustang throttle body. Here are a couple of great "how-to's" on how to make the Explorer throttle body a usable piece. It is rather simple. I would like to note that I tack welded my bellcrank on, and it has worked fine. I also did not have to change breather tube directions, and my TP sensor went right on with no mods.

http://oldfuelinjection.com/files/Explorer_throttlebody_fix.pdf

http://www.veryuseful.com/mustang/tech/engine/ConvertingExplorer65mmTB.pdf

Just one more thing I'd like to mention - I got my throttle body for 25 dollars, and it had the intake elbow, EGR, and TP sensor attached to it. I was able to sell the EGR vavle and TP sensor, and I literally made a 15 dollar profit.

Here is a picture of the Explorer throttle body on my Mustang. Please excuse the dust. This is right after it was painted, so it has paint dust on it.

 

[MustangShane]

The next thing you can harvest from an Explorer is the intake manifold. It is a HUGE upgrade over the factory Mustang intake manifold. It has flow numbers that are comparable to the GT40 or Cobra intake manifold. In fact, the bottom manifold is almost identical.

Here are some HP numbers comparing the GT40, Cobra, and Explorer intake manifolds. These figures were done by Super Ford Magazine:

The Explorer lower intake does not have a boss for the ACT sensor. You have two options. Either you can drill and tap the Explorer intake, or you can relocate it to the intake tube prior to the throttle body. This is where Ford moved it starting in 1994 on the Mustang. This is also what I did.

Here is a REALLY good write up on a swap to an Explorer intake:

http://www.allfordmustangs.com/Detailed/614.shtml

I thought I would put some GT40P head identifiers up so you can easily spot them in a wrecking yard. The P heads have "GT40P" in the casting in the valley near the rocker arms. That may not be easy to spot if the valve covers are still on them. There are also 4 bars on each end - and that may not be easy to spot if the accessories are still intact. My personal favorite identifier is "GTP" in the casting near the bottom right head bolt. There is a "P" directly above it that can only be partially seen with the valve covers on as well.

I gathered some photos (I like pics) via google and put this together below:

 

[MustangShane]

The next thing you can harvest from an Explorer is the intake manifold. It is a HUGE upgrade over the factory Mustang intake manifold. It has flow numbers that are comparable to the GT40 or Cobra intake manifold. In fact, the bottom manifold is almost identical.

Here are some HP numbers comparing the GT40, Cobra, and Explorer intake manifolds. These figures were done by Super Ford Magazine:

The Explorer lower intake does not have a boss for the ACT sensor. You have two options. Either you can drill and tap the Explorer intake, or you can relocate it to the intake tube prior to the throttle body. This is where Ford moved it starting in 1994 on the Mustang. This is also what I did.

Here is a REALLY good write up on a swap to an Explorer intake:

http://www.allfordmustangs.com/Detailed/614.shtml

I thought I would put some GT40P head identifiers up so you can easily spot them in a wrecking yard. The P heads have "GT40P" in the casting in the valley near the rocker arms. That may not be easy to spot if the valve covers are still on them. There are also 4 bars on each end - and that may not be easy to spot if the accessories are still intact. My personal favorite identifier is "GTP" in the casting near the bottom right head bolt. There is a "P" directly above it that can only be partially seen with the valve covers on as well.

I gathered some photos (I like pics) via google and put this together below:

 

[MustangShane]

If you are having issues with header/plug clearance, you can also use an Accel shorty/header plug. It can gain you some additional space to keep your plug wire boots from melting. The part number is P526S. It is a double platinum plug.

 

[MustangShane]

If you are having issues with header/plug clearance, you can also use an Accel shorty/header plug. It can gain you some additional space to keep your plug wire boots from melting. The part number is P526S. It is a double platinum plug.

 

[MustangShane]

A good friend of mine just completed a GT40P and Explorer intake swap on his Mustang. Here's a picture of the completed project.

One thing I found interesting with his swap is, with the BBK headers he had issues with cylinder 4 clearance. My headers are made by Brentech and my only plug that was close was cylinder 7 (see above). The Brentech headers are made in the exact same building that the BBK headers are made (BBK and Brothers Performance are next door to each other).

He also eliminated the A/C and smog pump while doing his swap. I have only eliminated my A/C lines and the drier (I think that's what it's called) that mounts to the firewall. He also added the electric fan. All of that ought to free up some horsepower.

 

[MustangShane]

A good friend of mine just completed a GT40P and Explorer intake swap on his Mustang. Here's a picture of the completed project.

One thing I found interesting with his swap is, with the BBK headers he had issues with cylinder 4 clearance. My headers are made by Brentech and my only plug that was close was cylinder 7 (see above). The Brentech headers are made in the exact same building that the BBK headers are made (BBK and Brothers Performance are next door to each other).

He also eliminated the A/C and smog pump while doing his swap. I have only eliminated my A/C lines and the drier (I think that's what it's called) that mounts to the firewall. He also added the electric fan. All of that ought to free up some horsepower.