Best carb, intake, cam combo for a GT-40 of of a explorer?

93green_gt

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Oct 10, 2007
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I need advice on a good setup for a GT-40 engine from a explorer( still not decided from what year), we are going to need a good carb, intake manifold as well as a cam and some valve springs while we are at it that work well together. This car is going to be a daily driver and will be occasionally used for the drags. We would like the best fuel mielage while still being able to achive the best at the quarter. We are planning on installing this engine on a notch with a 5-speed, and maybe in the future instal 3.73 in the rear.
 
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Probably an Edelbrock Performer or Performer RPM with an Edelbrock carb. Keeps it simple and matching. As for the cam...the FMS cams will keep you halfway decent for a DD and still make some power. As far as springs...just pick a set that is good for up to .600 lift and you'll never have to worry about them again.
 
That's what I had in mind. I was thinking a B cam. But not sure on the carb for some reason I feel more inclined with holley, and a performer or air gap intake would work. Before I buy this motor I know there are two types inner EGR or Exterior EGR, I think I need the inner EGR, is this correct?
 
I suggested the Edelbrock because it's cake to tune. I'm not opposed to Holley's either. I actually just bought a basically brand new 650 about two weeks ago.

EGR...get rid of it. If you have to stay emissions legal then that's a whole different issue in itself.
 
If you're running an aftermarket intake and you won't pass emissions, throw the stock EGR plate back on and give it another try. I speculate that if you get it tuned in real nice you'll pass just fine. What year is the notch?
 
This is for a 5.0 conversion on a 90 nothch. So correct me if I am wrong if it is inner EGR it's like the old style motors but if it is exterior EGR there would be some type of air comming from the exaust manifolds which would look horrible.
 
I personally think the RPM intake is overkill for the flow capabilities of the GT40 heads. These heads even ported won't flow well to 6,500RPM, so why add an intake that's rated for that kind of power band. I'd personally stick with the standard Performer intake (or equivalent) and take advantage of the GT40's small, high velocity runners and valves. You could build a really torquey, fun to drive street engine with a more conservative a set up like that. Save the higher flow intakes, for when you decide to swap out to higher flow aluminum heads.
 
I agree on the intake, I will probably go with the performer, is a 650 holley to much? I whant to have a decent fuel milege.

Naw, I'd probably stick with something in the 600-650cfm range myself. I'd also select a header in a 1 5/8 Long tube variety, keep the exhaust size limited to 2 1/2, then do some weight reduction, add Underdrive pulleys, keep the gears within the 3.55-3.73 range and do whatever else I felt necessary along the way to free up horsepower and weight in order to aid in fuel economy.

It would certainly be a fun street car.

Always resist the temptation to go overboard with mods, unless you're willing to commit whole heartedly to econemy hit you take with them and the driving style required to take advantage of their power production. I had a friend who built a Corvette that went in with the "bigger is better" attitude when he put together his 350 and ended up with an expensive, 15-second car that got 15mpg.
 
Do you think it is necessary to swap out the cam on a stock GT-40 engine from a explorer, I have heard that because of the cam they are best at low RPM, so it would be a good chice to swap out the cam and springs. I was thinking the minimal cam wich is the B-303, if I am not mistaken.
 
I don't off hand remember the profiles of the Explorer Cam, but I'm guessing if it's ground more for low end torque in order to move around a 4,500lb SUV like I imagine it is, you probably won't like it for a 3,000lb Mustang. Off idle torque and throttle response will be excellent, but it will likely start falling on its face fairly early in the power band, which isn't exactly what you want and hardly justify the better breathing top end you’re installing on the engine. A hard pull down low combined with a smooth steady pull all the way to redline is what most people consider ideal for a street car.

As far as aftermarket cams go, I've never been a fan of the Alphabet Cams sold through Ford or Crane personally. I'd look into one of the popular dual pattern grinds from CompCams or a custom unit from a company like Anderson Motorsports if it were my money. You’ll spend a little more initially for them, but their broad power production and excellent promotion of economy and drivability will be worth it in the long run.

The stock HO cam is unjustly criticized IMO. I ran my full weight '87 LX into the mid-13's on worn street tires with little more than stock ported heads with aftermarket valve springs and Crane 1.7 roller rockers, ported lower intake, under drive pulleys, full exhaust and a custom CAI...all backed with a conservative set of 3.55's out back. And I averaged 26mpg and had perfect drivability all the time.
 
OK here we go intake get a Weiand Stealth or an Edelbrock RPM. These will both give you room to advance due to they both have 7,000 rpm potential. The valve springs you will need for your GT40 P heads are a Crane #44308-1 they are like $125.00 and are good for rollers up to .550 lift. I would also stick with a Holley 600 or 650 cfm double pumper. That 670 Holley Avenger is also a nice piece to consider. Your gear would be fine at 3.55 or 3.73 I'd give the 3.73 the nod. Finally a Motorsport B or E cam would work fine and maintain driveability
 
I'm not gonna say much on the intake but as far as cams go I would look toward a TFS stage 1, crane 2030, or something similar. TFS also makes a nice valve spring kit for stock iron heads. A 600 to 650 holley will be perfect for a engine like this.
 
Ok. This is what I am thinking a Ederblock Performer intake a 600-650 Holley with a B-303 cam and some valve springs that are good for up to 0.6 lift all for a stock long block off of a Explorer( not sure on the best year to get it from).

Still not sure on the EGR. I do not know what it is or what's it for? I know some GT-40 motors have internally and other newer models have it externally. I do not know which would be best for a carburated setup. What are the pros and cons of either setup? Please help! O llea I want it to pass emission, because it will be a daily driver.

When I order my intake from Summit am I going to order it with EGR or w/o EGR?

GT-40P need special type of hedders, and GT-40 are the same as the 5.0's right?
What year is the best to get?
 
I would run an external EGR. You could disconnect it for every day street use and re-connect it for testing days :) Best of both worlds.

You're correct on the headers, however some headers will fit both. The key is that the primaries need to come out away from the head a bit to clear the plugs. The later GT-40P heads flow better than the standard GT-40's IIRC, however the P's do have smaller exhaust valves.
 
There is a GT-40 Explorer engine at a junkyard I would think it has the P series heads which leads me to belive that they are one of the best heads, so I will have to buy p series headders, and I think this motor should have a external EGR. Is it easy to dissconnect and connect the EGR? Would I need a carburated intake manifold w/ or w/o EGR? I need to know before I order it.