Engine upgrades?


Apr 23, 2023
So our 1995 GT 5.0 has an AF leak near the front of the engine. I haven't pinpointed it yet but it is a very small leak. Initial thoughts were t-stat housing but after looking again I'm leaning towards intake gaskets since there are pools on each side of the t-stat housing and the pool on the drivers side doesn't look like it could come from there.

Anyway, we are planning about a 1500-2000 mile trip mid-July and planning to take the Mustang. Car is 100% stock other than the 65mm TB and BBK CAI I installed last week. I have a slight itch to install GT40 heads and intake but not till winter. But if I pull the intake to replace the gaskets I'm thinking I might as well do them then? Talked to my machine shop and he gave me a ballpark of $400-500 to prep a set of heads. I can buy a set of freshly done GT40P's (4 bar) for $700. Another thought is to spend a little more if I can pick up aftermarket heads for around $1200? Plan would be to leave the stock cam. Over winter a shift kt and maybe 3.73's.

I just hate to pull the intake to replace the gasket and put the crap intake back on. And I don't think it makes sense to upgrade to theGT40 intake but leave the stock heads?

Hopefully I find the AF leak is simple so I have more time to make a decision or find parts but I would need to start this project in the next week or two.

Thoughts or opinions?
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With a stock short block (that includes the cam) I would run the GT40’s and the GT40 upper and lower. The P’s can pose spark plug boot issues but that can be solved but there really isn’t a lot of power difference for the additional $300 and being you already have the GT40’s. Again for the additional dollars the aftermarket heads will cost you are not going to notice the gains with a stock cam over the GT40’s or P’s.
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Misread that. I would highly suggest that you put the Trick Flow spring kit on the GT40's or P's. Typically you can find them a pull a part yards on the 96 and 97 Explorers but they started putting the P heads on them in late 97. With all that being said let's say you get them for $200, then a spring kit is $170ish and you will spend another $450 at the machine shop so a total of $820 if there is nothing major wrong with the heads. You can use your stock rocker arms and most likely your stock push rods so that will save you some money vs buying stud mount rockers but I would order some shims to get the preload correct. This is how you set and check preload on pedestal rockers that I took from a post that Michael Yount over on the Corral made. He is one of the guys on there that I have a lot of respect for and knows his stuff:

A pair at a time, rotate the engine manually until the lifters for the pair you're working on are on the base circle of the cam - that is - the valves would be closed if the rockers were on. Rotate the engine clockwise and watch the pushrods. First the exhaust pushrod will rise and fall; as it's almost back down, the intake will rise and fall. Just after the intake has come all the way back down - the two pushrods should be level once again - you're on the base circle for that pair.

Install the rocker and hand tighten it until you reach zero lash. I do this by rocking the rocker with one hand, and tightening the bolt with the other. Just as soon as the gap on both ends (pushrod/valve stem) disappears - you're at zero lash. At that point put a torque wrench on it and tighten to 18-20 ft-lbs WHILE YOU COUNT THE NUMBER OF TURNS it takes to reach the torque. It should hit the torque somewhere in the 1/4-1 turn range. If it takes more than 1 turn, you need to shim the rocker or put shorter pushrods in. If the heads or block have been cut this symptom may show up. Each .030" shim will reduce the number of turns it takes to hit the torque by about 1/4 turn. Most folks like to set them all in the 1/2 - 3/4 turn range. They may not all need shims; 11 of mine hit the torque in about 1/2 a turn. 4 of them needed 1 .030" shim to hit it 1/2 a turn; 1 of them needed 2 .030" shims to hit the torque in 1/2 a turn. If it takes less than a 1/4 turn on all the rockers, you need longer pushrods. If just one or two take less than a 1/4, you may be able to solve it by removing some material evenly from the bottom of the rocker fulcrum.

Removing all the plugs makes rotating the engine easier. When you crank them up, if they remain noisy after you've gotten them good and hot, you may have to go back through and 're-install' them while things are hot. I've had to do that on mine to quiet one or two of them down.

There are some cheap aluminum cylinder heads our there but do some research as they are typically garbage. If you make the decision to go with aftermarket aluminum heads then you will spend more money but you are only a camshaft away from a lot more fun.
Talked to my machine shop guy yesterday and he told me about $400 to clean and surface them and new valve seals with valve job. If they need guides then another $100. If they need springs and rockers then about $700 out the door, and I still have to buy them. But seems the cheapest aftermarket aluminum with the upgraded valve springs are about $1500?

$1,300 for the set out the door but you will need roller rockers and possibly push rods (read you should measure to make sure what you need).

$1,300 for the set out the door but you will need roller rockers and possibly push rods (read you should measure to make sure what you need).
I'll have to look into those. I had AFR's on my last car 20 years ago
Looking online for Explorer intakes and unsure of something. I see some have the internal EGR and some don't. Which do I need for a 1995 GT? Assuming internal? So the one with the EGR port in the intake inlet?
Is this what your looking for? Came off of a 97 or 98 Mountaineer with P heads.....
If you pick it up you can have it for FREE.... Lakeland Florida.....

Looks like it but I'm a little far away from you (Pittsburgh)...lol.
But believe that is the internal EGR? I think that is the one I would need but want to be sure. I plan to keep my EGR just for simplicity of not eliminating it.
Looks like it but I'm a little far away from you (Pittsburgh)...lol.
But believe that is the internal EGR? I think that is the one I would need but want to be sure. I plan to keep my EGR just for simplicity of not eliminating it.
I can't answer your question, its above my pay grade... Hopefully one of the more knowledgable FI guys on here can.....
As far as I know it will throw a code without it but the car will run.
Lol not all ways. I have zero emissions on mine well the egr is there plugged in but no vaccum to it, never trips the light. The BA egr lowers also have the boss for the act sensor on #5 while the non egr -BB lower don't, only really reason most want those. Still needs to be drilled and tapped though.
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