someone just explain the importance of these basic mods?

nicholasm617

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May 28, 2011
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so ive just come up with an 86 capri 5.0 in good shape, my first v8 (thankfully) so i wanna do stuff to it. whats the big deal about gt40 heads and explorer intakes? what kind of improvements can i actually notice from stock? (ive spent an hour searching and didnt see any answers # wise. i get the feeling its common knowledge i dont have yet.
 
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jrichker

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The GT 40 heads and explorer intakes out flow and out perform the stock Mustang equipment. The relative plentifulness and cheap prices in junkyards makes them an inexpensive upgrade to an otherwise stock engine. The 1995-2000 V8 Ford Explorers and Mercury Mountaineers are found in a lot of different junkyards and the prices for parts is reasonable in most cases. GT40 heads and Explorer intake manifold are probably worth 30-40HP when combined. The heads will need new valve springs and a valve job if you hope to get this kind of HP improvement. What you actually get depends on having a larger MAF & throttle body and basic good engine health to take advantage of the improved breathing capacity.


On a budget? do the junkyard upgrade...

Gears - 87-88 T-Bird Turbo Coupe rear axle - disc brakes and 3.55 or 3.73 gears in one package for $125-$300. Add another $100-$200 or so to complete the brake upgrade.

94-95 Mustang GT MAF - $40-$100. It is 70 MM instead of the stock 55 MM on regular stangs built prior to 94. It uses a slip on duct on the side that goes to the throttle body and a 4 bolt flange on the other. You need a flange adapter to fit the stock slip on air ducting that goes to the air box. Wiring plugs right in with no changes. *1 *2

95-97 Ford Explorer intake manifold & throttle body $150-$300. The intake manifold flows 220 CFM +, much better than stock. Throttle body is 65 MM, bigger than the 60 MM on stock stangs. I got a 96 with EGR passages that match the stock setup, so my smog gear works just like factory. You’ll need a 65 MM EGR spacer & new gaskets for $65-$90 so you have a place to mount the EGR & throttle linkage.

3G alternator from 94-95 Mustangs or other Ford. $20-$120. A must have to make the electrical system work like it should or if you have an electric fan. You’ll need a 4 gauge power wire and a 125-135 amp fuse to go with it about $15- $30.

Lincoln MK VIII electric fan -$40-$160. Free up some HP by not having to drive the stock fan. The 3G alternator upgrade is a must have prerequisite before you do the MK VIII fan. You won’t have enough electrical power if you don’t do the 3G upgrade.

Aluminum driveshaft: (courtesy of shawn13) It needs to be from a 92-93-94 Aerostar AWD. It measures 45 ½” center of the front U-joint to center of the rear U-joint. You will need the U-joint, part #PUJ353 from NAPA. The Canadian NAPA pat number is 1-0134BF. It should bolt right up after the U-joint swap.
Note: This driveshaft is not an exact duplicate of the Ford Racing part. It is 3” in diameter while the Ford Racing part is 3.5” in diameter.

Use a piece of string and wrap it around the driveshaft. Make a mark on the string where the ends overlap.

Measure the length of the string:
On the 3" AeroStar driveshaft the string will be 9.42" or about 9 7/16" long.
On the Ford Racing 3.5" driveshaft the string will be 10.99" or about 11" long

*1.) Metal flange adapter Ford MAF Adapters - Air Filters - Kurtz Kustomz Motorsports, Inc. KKM Buy the TR70 for $40. Or spend some time on eBay looking for one that may fit.

*2.) MAF & sensor interchange
The 94-95 Mustang 5.0 MAF & sensor is also found on:
1995-94 Mustang 3.8L F2VF-12B579-A2A,
1994-92 Crown Victoria 4.6L F2VF-12B579-A2A,
1995-94 Mustang, Mustang Cobra 5.0L F2VF-12B579-A2A,
1994-92 Town Car 4.6L F2VF-12B579-A2A,
1994-92 Grand Marquis 4.6L F2VF-12B579-A2A,
Evidently the –A1A, -A2A, AA, etc. on the end of the part number is a minor variant that did not change the operating specs. You should be able to ignore it and have everything work good.
 

cammed89lx

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afr's are a buttload but you really cant beat the performance. By the time you get them, and have them on the car you wont be disappointed. They are one of the highest quality heads available.
 

Kdubslugga

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Nobody has mentioned it so I figured i would say it. There is a difference between gt40 and gt40P heads. Gt40Ps come off all the Explorers and Mountaineers, while the gt40's which are slightly better are off the 93 Cobra
 

No.11

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^ pre 97 explorers also have the gt40, with the 97+ having gt40p. and... most would argue that gt40ps are actually better. however I have yet to see a real conclusion as to which is best.
 

Maryland Stang

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Your best bet is to find a set of Ps that someone else put money into. I got mine with Manley 1.94/1.60 valves already in them. I sent them to the shop and had them ported and shaved. For about $750 I have a really nice set of heads.
 

FastDriver

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Don't mean to sound arrogant, but I really don't see the point in doing all that work on a car to put on a set of heads that are only going to pick up 30-40 hp. Then again, I'm fortunate to have the money to afford the nicer stuff. So, I'm not knocking those who choose to go that route for financial reasons.

In any event, 93 mustang cobra had GT40 heads, and essentially equivalent Cobra intakes and they made 225-235 rwhp as compared to stock 5.0s that made 190-200 rwhp through manual trannies. Keep in mind that the Cobra had some other parts that helped out too and a cam that hurt a little. I think that without any other significant changes, you should see 30-40hp as already stated earlier in this thread.
 

f8tlfiveo

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Go on eBay and look up Odessa cylinder head.. Gt40p heads delivered to my door for 370 about a year ago.. No core charge if you buy them on eBay. Remanufactured, new valves 1.54 exhaust valves instead of 1.46 I think.. They were clean and ready to install with new springs.. I added 1.7 roller rockers with the stock cam.. Runs good no clearance issues..
 

Mustang5L5

A little massaging and it went right in
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I have always been under the impression that the GT40P's without the internal EGR flowed better.
Not necessarily flow, but the revised plug location gives a better flame front to the incoming fuel charger resulting in "better" overall combustion. I've always felt the gt-40P were superior to gt-40. The "p" is for performance
 

LarsD

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Not necessarily flow, but the revised plug location gives a better flame front to the incoming fuel charger resulting in "better" overall combustion. I've always felt the gt-40P were superior to gt-40. The "p" is for performance
That's it, I forgot about that too.
 

Maryland Stang

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Don't mean to sound arrogant, but I really don't see the point in doing all that work on a car to put on a set of heads that are only going to pick up 30-40 hp. Then again, I'm fortunate to have the money to afford the nicer stuff. So, I'm not knocking those who choose to go that route for financial reasons.
Exactly. Going with aluminum aftermarket heads usually involves a whole lot more cost than a lot of people realize. A set of decent aluminum heads is going to set you back at least $1200 shipped. You may also need a set of bolt spacers, ARP bolts, pushrods, rocker arms and a fancy intake to match the fancy heads. Before you know it you've spent $3,000.

You can bolt GT40Ps on the way they are. If you're not particular you can use the original pushrods and rocker arms. Or you can go all out and get a Explorer intake, B or E cam and some FMS 1.7 rockers and have it done for half the cost of the aluminum heads.
 

v8stang289

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Apr 22, 2008
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Something else you have to worry about with an 86 5.0 is piston to valve clearance when running anything other than stock E6 heads. The flat top pistons in the 86 motors limit what you can run, so always check to be sure there is adequate clearance.