Grabbin' Asphalt
5 Year Member
In short, if you go aluminum don't dabble with the gt40x, if you're in low budget mode, stay with cast iron gt40 (p) heads 
Fox Blown Head Gasket-upgrade Ideas
- Thread starter stang89bidges
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gearheadboy
15 Year Member
If you find any more AFR 165's for $500.00 let me know. Meanwhile I prefer the GT40 over the GT40P only for personal preferences such as ease of spark plug replacement and lack of burned boots. I also like the fact they have no thermactor ports and larger valves.
Well maybe not the AFR's
But def can find the tfs 170cc heads in that price range. Especially with the release of the new 11r head design. Fwiw not knocking gt40 guys. I'd just spend the extra for alum heads
gearheadboy
15 Year Member
Oh I wholeheartedly agree. I'd prefer aluminum. I just hadn't seen any real deals that I could put my hands on and look at before a purchase. I'd have to buy them local. And "P" heads have some good features. I'm just too old to jack with some of the issues.Well maybe not the AFR's
mikestang63
SN Certified Technician
couple of things I'll add. You can make about as much power with a good set of GT40 iron heads , good springs and valves as some of the cheaper aluminum heads- give or take 20-30 hp which you will never know. They also will handle the heat of the supercharger better and cost about 1/2. That being said, if it were me. I'd do it right the first time and bite the bullet- get a set of TW 170 or better yet the new 11R heads.
Full disclosure- I swapped my stock top end for an explorer intake and heads last year and should have waited to put on the TW ones.
For head gaskets, I would void the MLS on supercharged applications as you want the head gasket to be the fuse in the system, not your motor. Plus the surfaces have to be perfectly smooth for them to seal. I have run the Felpro 9333 with no problems for years.
Full disclosure- I swapped my stock top end for an explorer intake and heads last year and should have waited to put on the TW ones.
For head gaskets, I would void the MLS on supercharged applications as you want the head gasket to be the fuse in the system, not your motor. Plus the surfaces have to be perfectly smooth for them to seal. I have run the Felpro 9333 with no problems for years.
Care to elaborate? Curious as to your theory behind this. (PS I don't want to start a Doritos Taco Food Fight, just curious)
mikestang63
SN Certified Technician
Sure. Iron heads do not dissipate the heat as fast as alum heads and keep it in the cylinder longer. Alum heads don't dissipate the heat as fast, but also tend to not warp as fast as alum heads to to overheating. Now that has nothing to do with the amount of hp the heads will make, or the amount of timing you can run the heads at. Simply talking about the heat levels.
I'm picking up what you're putting down! Thanks. I didn't want someone to misconstrue that statement.
7upstang91
10 Year Member
AFR heads can be had cheap. I'm in the process of selling the pair off my car (local to me, already spoken for) for $650.00. Can I get more for them perhaps? Personally, I want a no haggle price to get rid of them. Needless to say, they are out there.
mikestang63
SN Certified Technician
165's? They are a decent entry level head. Personally I would rather get the TW170's. Bigger valves, so much more room to grow. However, for $650, if those heads are not beat up,thats a good price.
7upstang91
10 Year Member
Yes sir, good enough for me to go mid 11s. But deals are out there, just got to find them. I'm selling mine fully assembled.
Usually holding heat in the cylinder head is a bad thing. Also, all the aftermarket heads run a full .750" deck unlike the factory iron heads. They actually warp less.
Kurt
Kurt
Well boys it looks like the head gasket really is blown. I will know for sure tomorrow. Where can I get a set of these GT 40 heads for $250? What will I need to do to them?
mikestang63
SN Certified Technician
Couple of options
JY - any 93-96 Explorer/ Mountaineer
CL or classifieds here or Corral
Ebay
GT40's have 3 bars on the front of the heads, GT40P's have 4 bars. The P heads will require certain brand headers to fit the different angle of the spark plugs.
You'll want to check for warpage, cracks ( magnaflux), have them cleaned, maybe a light mill and upgrade the springs to match your cam. I used the TFS springs from Summit for around $150. They come with the seals, and retainers.
Expect to spend about 3-400 total if you are prudent. Don't put more than that into them, as for a few hundred more you can find a set of used alum heads.
I'm thinking I may just keep my heads and have them cleaned up. Just too expensive right now.
What about this?
http://www.latemodelrestoration.com...-50L-75Mm-Black-Pro-M-Mass-Air-Meter-For-36Lb
with these:
http://www.latemodelrestoration.com...acing-Mustang-34Lb-Fuel-Injectors-M-9593-Lu34
What do you think? Do these two work with each other? This would get rid of my FMU on the vortec SC.
What about this?
http://www.latemodelrestoration.com...-50L-75Mm-Black-Pro-M-Mass-Air-Meter-For-36Lb
with these:
http://www.latemodelrestoration.com...acing-Mustang-34Lb-Fuel-Injectors-M-9593-Lu34
What do you think? Do these two work with each other? This would get rid of my FMU on the vortec SC.
mikestang63
SN Certified Technician
PRO M MAF and matching 42lb injectors, a tune and be done with it. The other choice I like is a 90MM LMAF which you can buy new for like $100 I think and then have the tune done.
http://www.buyfordracing.com/products/90MM-LIGHTNING-AIR-METER.html
http://www.buyfordracing.com/products/90MM-LIGHTNING-AIR-METER.html
I can't find 42lb injectors. Either 34lb, 39lb, and 47lb injectors. Also, that 90MM MAF is for a 2001-2004. Is that going to even work for my 89?
You will have to have a custom tune to run the LMAF. Not a biggie since you're going to need a tune to run the 42s if you want the car to run like anything other than a bag o crap on the street.
Oh, I don't know about that. I've got a set of GT40X's on my 331 and am quite happy with them. Car pulls strong all the way to red line and the heads are about as direct bolt on as you're going to get. Not the performers that the Trick Flows or AFR's are, but still comparable...and still a step above the GT40/ GT40p's.In short, if you go aluminum don't dabble with the gt40x, if you're in low budget mode, stay with cast iron gt40 (p) heads
And don't be fooled, refurbishing a set of GT40/GT40P's can break the bank in a hurry. When all was said and done, my GT40X's only cost me about $200 more than a set of GT40 iron heads after the necessary machine work and valve spring upgrade.
Also, the pedestal mounted rocker arms only become an issue at sustained high RPM. The stock ECU cuts fuel at 6,250RPM anyway, so it's really a non issue for 95% of owners.
Comparative AFR's and Trick Flows will make slightly more power, but if you've got to buy stud mounted rockers, or longer pushrods, they can end up being a fair bit more expensive. If you've already got the pedestal mounted roller rockers and can find a set of GT40X heads for a good buy, they're well worth the investment.
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