Progress Thread Update And Opinions On My Build Plan And Some Questions.

Bob91vert

Member
Sep 8, 2015
89
22
15
Hey folks,
Some of you have probably seen my couple posts on my 91 GT Vert. I bought the car not running and trailered it home.
Working with my best bud on the car as he is a very seasoned mechanic as well a top notch diagnostic guy. We were suspecting a head gasket or worse as when I got the car home and we finally diagnosed the computer being bad, I plugged in the new/used to me comp. and the car fired right up. Time to fill the coolant!
I started with just the hose and water was coming out from under the car as fast I could put it in. I crawl around a bit and 2 freeze plugs are gone on the drivers side and the one under the starter is half way out and sideways leaking water onto the starter. I replace the plugs and re-fill.
I knew this car had some kind of possible coolant issue as the PO used just plain water and of coarse it turned Orange colored. Well this orange was on the firewall, which led me to noticing the heater cores broken off beaded tube. You could also see the stains up near the rad and under the car like it was moving when it over heated. This all helped to negotiate a good price.
So I have the car running sweet and got the new top frame on. Working on interior and small stuff now. While working on it I have been taking it on short drives to see how everything is working. While the drives go fine when I stop I am getting some bubbling in the coolant res. The cap does steam a little but never a complete overheat. If I take the rad cap off before it gets hot it will kind of slowly push coolant out.

So I start looking into the cooling system. upon checking the car had no thermostat in it so I replaced that, Also threw a new Rad in as the one in the car felt heavy like it was clogged with the orange stuff.
I had to verify temp and the temp gauge was not working. So we used a device that reads surface temps. We got 230°F at the rad core inlet after the car had gone for a hot lap or 2. Then replaced the sender and the gauge began working. Went near red when I fired it up and let it run.

Thought well maybe the water pump was bad even if it wasn't leaking. Upon removing it seemed to be in fine shape as far as I could tell.

I was skeptical it was not burning coolant out the exhaust though. I thought I could see it once in a while but wasn't sure. Checked the oil many times to make sure it never had coolant in it.

Then my buddy brought home a device that reads whether there is exhaust in the coolant. (should have done this first). Sure enough there is exhaust in the coolant.

Time to tear things down. Got it torn down and one of the head gaskets is leaking. Short block seems to be in great shape. The cylinders look perfect and we agreed that the short block was in good shape. The car is advertised as having 82,000 on it. And it ran as good as any during these drives. Never smoked and for stock was fun as heck.

I have owned a couple of these long ago and have always wanted another since now I have money to throw at one. So a stock motor was not going to work this time.

I expected to get the new top on and interior done before a motor build but here I am with a short block sitting in the car and no way I'm putting it back together with the stock parts.

Me and the wife bought this car to drive it in the spring and summer on nice days and such. We want power but want to stay N/A. I don't want a race car just a fun driver that performs in all levels of driving.

So my thoughts are simple. GT-40 intake and heads, stock cam? Explorer TB and MAF, good headers and complete exhaust.
Thinking of using the 1.72 rockers to lift the stock cam up a bit. New push rods ect.
355 or 373 rear gears. The car is a manual.
Nothing much more than the 1000's already out there have.

Cam question.
Will my stock cam be good with the 1.72 rockers? Can I go bigger without effecting drive ability or messing with the computer? What is a good cam for my application if I can go bigger? How much more power can I get from a bigger cam for the extra money for cam, lifters, chain ect as opposed to just rockers and push rods?

Heads.
I can get re-manufactured 96 explorer GT-40 heads for 250 each. Any reason I should go with some others in aluminum?

Smog equipment.
I live is a county that does not require emissions. Should I remove it all?

I'm looking for others thoughts and concerns on any engine aspects. Opinions ect.

There will be allot more done to this car. Sub frame connectors, suspension, brake upgrades ext. And I'm sure I will have more questions as the build rolls on.

Right now Im forced to focus on the engine.

Thanks for any reply's!
 
  • Sponsors (?)


Adding an intake,gt40 heads,etc and keeping the stock cam won't make very much power(around 235-250rwhp). You can use the 1.72 RR's with the stock cam. You have to add springs to those heads even if you use a stock cam. The stock explorer heads valve springs aren't strong enough. So by the time you add it up you're almost to the cost of a good aluminum head like the TFS 170cc. Which flow significantly better and you save about 50lbs. If going with a better head I'd spend the money and get a cam. You should look into the trick Flow topend kit(it has everything you need). That kit produces about 285-300rwhp. You will need more fuel injecters(24#) and pump,an aftermarket MAF sensor(pro m) programmed for the 24#inj. The stock computer is fine at this level and really no need for a chip(but there is some fine tuning that can be done with one).
 
Even with the stock cam that combo makes a great street car. Rather than go through the hassle of a rebuild I would find an explorer long block and transfer over the mustang timing cover and accessories. Either keep the stock mustang cam or put in a decent ots unit. End goal will be an easy 260-270rwhp engine that will have stock street manners. I pulled my explorer engine for less than 200 dollars. Total investment by the time I turned the key was around 500 after gaskets/fluids.
 
I had a stock shortblock and installed Thumper ported/polished GT40P's, a Trickflow upper and lower intake, stock cam and 1.72 roller rockers. I know you arent talking about ported heads necessarily, but just giving you my first hand advice. While the car had more top end, it either lost torque or shifted to much higher RPM range (never dyno'ed it). I didnt realize it until I put it back to stock to trade it in. On the way to the dealer, I was astonished at how much more fun it was to drive around town in stock form. To be honest, if I were to do it all over again, I think your best bet is some AFR heads with a custom cam for torque, or else a trickflow HCI kit. At least that is put together to give all around gains. Since you arent going to track to run it out, build it for torque for the street. Again, just my two cents.

Edit: Yes, ditch the smog equipment if you dont need it, as its just added weight and another set of bearings to go bad. Dont bother with the "smog eliminator pulley" kits, just buy a shorter belt. You will need to weld the hole shut in the H/X pipe from the tube that runs down to it. A lot of people either upgrade the mid pipe, or weld a bolt in the hole. I had 3.73 gears with a T-5 (stock manual transmission), and first gear was all but useless. I would vote for 3.55's. This will help you obtain a little better cruising RPM and fuel economy during highway driving.
 
Last edited:
I agree with stykthyn. You should get stiffer springs with the new heads...not expensive or really hard to do with the right tools. The stock 93 cobras used 1.7 rockers and the motorsports e cam. So your horsepower with 24 injectors, maf, gt 40 heads, explorer intake, and e cam would be about the same as a 93 cobra....that was great horsepower for 1993. It would make a good reliable weekend driver and wouldn't suck up too much gas. The egr valve is different on some explorer intakes. I may be bashed for this but I do believe in keeping the egr functional. It cools combustion temps and doesn't rob any horsepower. The air pump and thermactor tubes are some of the first things I ditch. I'm all about power and upgrades my car is full of goodies. The downfall with gt40 heads is that a lot of people lose the egr and you have to buy headers that will work with them.
 
I have stock cam with 1.7 roller rockers and it pretty much kicks ass. I have no hesitation in recommending anyone else do the same. I did do mild porting on the GT40 heads and slapped in TFS springs and pushrods. With my explorer intake and 65mm explorer TB, it screams to 6k rpm no problem. I need drag radials to keep from spinning wheels in 1st and second. I have 3.73 gears because that is what was available at the time they were installed. If I had a choice, knowing how it behaves now, I would have gone with 3.55's.

I'm still running stock 19lb injectors but I have to crank the fuel pressure up to satisfy the extra hunger for fuel. My wideband 02 was worth every penny.

I'm midway in a V3 install now. Cant wait to see the outcome. I stuck with a stock cam knowing how well it works with boosted applications. With the V3 comes 30lb injectors and calibrated MAF.

You're on the right track if you want a car with good street manners that also puts out. If you match everything, it will be a nice setup.
 
I agree with stykthyn. You should get stiffer springs with the new heads...not expensive or really hard to do with the right tools. The stock 93 cobras used 1.7 rockers and the motorsports e cam. So your horsepower with 24 injectors, maf, gt 40 heads, explorer intake, and e cam would be about the same as a 93 cobra....that was great horsepower for 1993. It would make a good reliable weekend driver and wouldn't suck up too much gas. The egr valve is different on some explorer intakes. I may be bashed for this but I do believe in keeping the egr functional. It cools combustion temps and doesn't rob any horsepower. The air pump and thermactor tubes are some of the first things I ditch. I'm all about power and upgrades my car is full of goodies. The downfall with gt40 heads is that a lot of people lose the egr and you have to buy headers that will work with them.
93 cobras came with an E cam? Might wanna look into that one again.
 
  • Like
Reactions: 2 users
93 Cobras actually came with the same came the 5.0l thunderbirds got .


Sent from my iPhone using my fingers while my auto correct makes me seem illiterate
 
Wow, love all the input and first hand experience! Thanks guys!
So it sounds like for what I want the GT-40 NON "P" head's with the explorer intake, 1.7 rockers, push rods, valve springs, 65 mm TB, 24# injectors, MAF to match, more fuel, nice headers, off road H pipe, and a new cat back system with 3.55 gears in the rear I should have easily what I'm after.

I'm still pondering an E-303 cam setup. And TF 170 heads. Money is no object. And I can and will do all the work. I just don't know if I need that much more power. I'm 48 and me and the wife just want a semi mild mannered hot rod to drive on nice days. This car is a garage car.

Questions:
What is an OTS unit? "Either keep the stock mustang cam or put in a decent ots unit"
What is a wide band 02? "My wide band 02 was worth every penny"
Can someone tell what the lift is for a stock cam with 1.7's?
Lift on a E-303 with 1.7's?
Is there a GT-40 intake that has a provision for an EGR?
 
If money is no object just click add to cart on a trick flow top end kit. It is a complete package, no guess work or opinions involved. Solid 300 rwhp.

But to your original question ots= off the shelf as opposed to a custom ground cam.
A wideband o2 is simply a gauge that reads your air to fuel ratio at the o2 sensors. It will tell how if your car is running lean or rich and how much so. Valuable tool in tuning.
96-97 explorer/ mountaineers had the 5.0 with the egr provisions and the non p heads.
 
  • Like
Reactions: 2 users
Wow, love all the input and first hand experience! Thanks guys!
So it sounds like for what I want the GT-40 NON "P" head's with the explorer intake, 1.7 rockers, push rods, valve springs, 65 mm TB, 24# injectors, MAF to match, more fuel, nice headers, off road H pipe, and a new cat back system with 3.55 gears in the rear I should have easily what I'm after.

I'm still pondering an E-303 cam setup. And TF 170 heads. Money is no object. And I can and will do all the work. I just don't know if I need that much more power. I'm 48 and me and the wife just want a semi mild mannered hot rod to drive on nice days. This car is a garage car.

Questions:
What is an OTS unit? "Either keep the stock mustang cam or put in a decent ots unit"
What is a wide band 02? "My wide band 02 was worth every penny"
Can someone tell what the lift is for a stock cam with 1.7's?
Lift on a E-303 with 1.7's?
Is there a GT-40 intake that has a provision for an EGR?
If money is no object and you want a mild mannered car, yet still make decent power, this is all you need:

Trick Flow Mustang Top End Kit, w/ Street Burner Intake Silver (87-93) 5.0L

and OTS cam means "off the shelf" as opposed to a custom cam. You wont need a custom unit.
a wideband O2 sensor reads a larger range air fuel ratio range than what is in the car now and it comes with a gauge for real time readouts.
you can get an explorer intake with EGR provisions, but I still think the link I provided is your best bet.
 
  • Like
Reactions: 1 user
I'm good with the cost of a kit like that. Would that power kind of eliminate the need for the 3.55 gears? Gears are going to make it pull even harder.
I think we have gone over and beyond what I wanted. But the input is good. Will I need bigger injectors, fuel pump, MAF ect? What size throttle body works best?
Thanks!
 
You can use stock maf and tb if you want, but honestly you will want to upgrade to at least a 70mm tb and the 94/5 maf is 75mm iirc and practically is a bolt on unit. 24lb injectors minimum.