not to hijack but, can someone explain the diff between all these ford intakes and heads.. like what's the difference between gt40, gt40p, gt40x, etc. Like some people say the intakes are better off the 97+ explorer blab bla.. i've got myself all confused.
This has been answered at least a bajillion times already, and from now on you should try searching the forums first, but....
Cast Iron Gt-40 Heads: These heads came stock on the 1993 Mustang Cobra, and the early Ford Lightning pick-up trucks, as well as some earlier Ford Explorer's. These heads are easily identifiable by 3 vertical bars that are cast into the ends of the heads, and "GT" is also cast into the heads. They retain the stock spark plug angle and also accept the Thermactor emissions crossover tube. They have 1.84/1.54 size valves, and flow significantly better than stock heads, but also weigh a small fraction more. These were sold by Ford Motorsport for a time as part # M-6049-L302 (bare) and L303 (assembled). As part of the GT-40 kit that Ford Motorsport sold for a while, these heads were issued a CARB E.O. # for street legal use in California.
Cast Iron GT-40P Heads: These heads came stock on 1997-1/2 Ford Explorers and Mercury Mountaineers and were used until Ford stopped using the 5.0L in production vehicles. They are easily identifiable by 4 vertical bars that are cast into the ends of the heads, and "GTP" is also cast into the heads. They have no provision for, and do not accept, the Thermactor emissions crossover tube. They have a relocated spark plug angle which bring the spark plug electrode more to the center of the combustion chamber. These heads require special attention to headers, since most headers will interfere with the revised spark plug angle. They have 1.84/1.46 sized valves, and compared stock to stock will flow even better than the standard GT-40 heads. These were sold by Ford Motorsport for a time as part # M-6049-P303 (assembled). While these heads are supposed to be very efficient and burn very clean, they are not street legal for use in California. The combustion chambers of the "P" heads were smaller than the ones on the standard iron GT-40 head and stock E7TE, and were good for a slight increase in compression.
Aluminum GT-40Y Heads: Unlike the Iron GT-40 and GT-40P, aluminum GT-40 heads from Ford Motorsport were never used in production cars. These heads have a standard spark plug angle, 1.94/1.54 valve sizing, and do accept the Thermactor emissions crossover tube. 160cc intake ports. They DO NOT have a CARB E.O. #.
Aluminum GT-40X Heads: Same as GT-40Y in terms of valve sizing, spark plug angle and emissions. Offered in two combustion chamber sizes, 58cc and 64cc. 178cc intake ports. Intake Flow 240cfm @ .550, Exhaust Flow 170cfm @ .500. DOES NOT have a CARB E.O. #.
Ford Explorer 5.0L Intakes: They are essentially the same as the intake that came stock on the 1993 Cobra Mustang. Since both the 1993 Cobra intake and GT-40 Tubular intake have essentially the same lower intake, the lower intakes between the 1993 Cobra, Tubular GT-40, and Explorer's are essentially interchangable. What you need to watch out for is that some later 5.0L explorers were not drilled and tapped for the ACT (Air Charge Temperature) Sensor. The upper intake on the Explorer's also are slightly different visually from the '93 Cobra style. There have been extensive, exhaustive write-ups on the subtle differences in Explorer intake manifolds, use your search button for more detailed info.