TCCoA Forums banner
1 - 10 of 10 Posts

·
Registered
Joined
·
57 Posts
Discussion Starter · #1 ·
I have a 92 tbird sport 5.0 with Mac long tubes and i am looking into getting heads from a 98-99 explorer which i think are GT40P and i will also grab the intake manifold.
With this combination on my 5.0, what else should i throw on while i do the upgrades? I was thinking cam and spring but should i change the pushrods or rockers?

what kind of hp gains should i expect from this upgrade and how much with a cam?

thanks for any help!

Also i might port and can this head take bigger valves? And is this worth it? Thank you
 

·
Registered
1991 Mercury Cougar LS 5.0 in restoration
Joined
·
1,772 Posts
If you want bigger valves, buy used aftermarket heads, as you'll spend as much in machine work. If you do go with these heads, get new springs, and pushrods, as you can't be certain proper geometry on a different engine with different cam. I would recommend a mild cam upgrade if you're going through this much work. A "B" cam is good, but a comp cam extreme energy cam would actually be better. Something in the 0.500 lift arena with mild duration would be great.

HP with the heads and intake would be around 275. With a cam, you're talking 325ish if everything else is up to snuff.

The headers may work with 90* spark plug boots
 

·
Registered
Joined
·
57 Posts
Discussion Starter · #4 ·
IIRC GT40p heads won’t work without custom headers due to the spark plug angle, the 1996 Explorers used the Cobra GT40 heads which can be used with the usual Mustang headers that (sorta) fit our chassis

Heres a thread that some people are saying the mac long tubes fit with the GT40P so now im confused if you say they wont work?

If you want bigger valves, buy used aftermarket heads, as you'll spend as much in machine work. If you do go with these heads, get new springs, and pushrods, as you can't be certain proper geometry on a different engine with different cam. I would recommend a mild cam upgrade if you're going through this much work. A "B" cam is good, but a comp cam extreme energy cam would actually be better. Something in the 0.500 lift arena with mild duration would be great.

HP with the heads and intake would be around 275. With a cam, you're talking 325ish if everything else is up to snuff.

The headers may work with 90* spark plug boots
Would it be better/more cost effective if i got aftermarket heads? The GT40P's would cost me around 100$ CAD at Kenny U-Pull which is their price for heads but im assuming its for each head so 200$. Or should I just grab upper and lower intake from the explorer (30$) and find some aftermarket heads? I dont have a too big budget but i am trying to collect parts for when i get back home to my car from school.

Thank you
 

·
Super Moderator
Joined
·
8,434 Posts
GT40P heads won’t work. The spark plug angle is different and it will hit the headers and burn up the plug wires. Regular GT40 heads off a 96/early97 Explorer will work, and they are an improvement over the stock E7s, but in my opinion not really worth all the work of a head-swap for the 30-40hp you will pick up from them. If you are willing to spend a boat-load of time porting them, GT40s can be very good, but by the time you buy the heads for $2-300, get a good valve job done for another $300, and spend 40+ hours with a grinder breathing in rust, the thought of buying a used set of aftermarket aluminum heads for $1000 starts looking a lot better, especially considering you will get better performance plus saving about 75lbs off the front end of the car. However if you can get the Explorer intake manifold for $30, that is a hell of a score!
 
  • Like
Reactions: JacobM

·
Registered
Joined
·
57 Posts
Discussion Starter · #6 ·
GT40P heads won’t work. The spark plug angle is different and it will hit the headers and burn up the plug wires. Regular GT40 heads off a 96/early97 Explorer will work, and they are an improvement over the stock E7s, but in my opinion not really worth all the work of a head-swap for the 30-40hp you will pick up from them. If you are willing to spend a boat-load of time porting them, GT40s can be very good, but by the time you buy the heads for $2-300, get a good valve job done for another $300, and spend 40+ hours with a grinder breathing in rust, the thought of buying a used set of aftermarket aluminum heads for $1000 starts looking a lot better, especially considering you will get better performance plus saving about 75lbs off the front end of the car. However if you can get the Explorer intake manifold for $30, that is a hell of a score!
Yeah I got to doing more research and it seems like alot of work for saving a bit of money on the heads for going with gt40p's, but yeah i will go grab those upper and lower intakes, theres 2 in the junkyard right now so if i have the time i will go and grab them both they seem to be reselling for alot.

Should I grab anything else other than Upper and Lower intake? like the 90 degree that comes off of them and TB or Maf? is any of that stuff good or can I just bolt back my TB off my car the same way it is but on the explorer upper?
 

·
SuperNewbie
1995 Thunderbird LX Missing 4.6 MIssing Trans Red
Joined
·
4,059 Posts
All the advice above is worthwhile. Far as the heads go, even if you pulled them and resold them you can make a little money.
 
  • Like
Reactions: Zep5.0

·
Registered
Joined
·
57 Posts
Discussion Starter · #8 ·
GT40P heads won’t work. The spark plug angle is different and it will hit the headers and burn up the plug wires. Regular GT40 heads off a 96/early97 Explorer will work, and they are an improvement over the stock E7s, but in my opinion not really worth all the work of a head-swap for the 30-40hp you will pick up from them. If you are willing to spend a boat-load of time porting them, GT40s can be very good, but by the time you buy the heads for $2-300, get a good valve job done for another $300, and spend 40+ hours with a grinder breathing in rust, the thought of buying a used set of aftermarket aluminum heads for $1000 starts looking a lot better, especially considering you will get better performance plus saving about 75lbs off the front end of the car. However if you can get the Explorer intake manifold for $30, that is a hell of a score!
Should I pick up any of the extra parts while im grabbing the intakes at the junk yard? Like the TB or MAF? or any other parts worth grabbing? Thanks
 

·
Super Moderator
Joined
·
8,434 Posts
Definitely take the throttle body. If nothing else, you can re-sell it. I would actually just pull the intake with the elbow and throttle body still attached, then hopefully the junkyard will only charge you for the intake. If the fuel rails are the return style and are in good shape (not rusty), I would be interested in those.
 
  • Like
Reactions: JacobM

·
Registered
Joined
·
57 Posts
Discussion Starter · #10 ·
Definitely take the throttle body. If nothing else, you can re-sell it. I would actually just pull the intake with the elbow and throttle body still attached, then hopefully the junkyard will only charge you for the intake. If the fuel rails are the return style and are in good shape (not rusty), I would be interested in those.
Will do thanks!
 
1 - 10 of 10 Posts
Top