X303 ... Y303 heads

[SVT Fun]

Looking for individuals with subjective experience with these Ford heads. Any comments about horsepower gains. (i.e., before and after dyno pulls)

 

[Teal93]

I dont know how much power i gained but I dropped 6 tenths off of my times from 13.7 to 13.1. I bought the X heads when they first came out many years ago and now they are supporting 500HP to the tires with my turbo with 10psi. I think they are good heads for the money.
Later
Robert

 

[~Ray~]

I wouldn't use either of them heads if I were you. Just get some AFR 165's or Edelbrock Performers they will blow any GT-40 head out of the water, NA or Blown :coolman:

 

[9T3SVT]

I wouldn't use either of them heads if I were you. Just get some AFR 165's or Edelbrock Performers they will blow any GT-40 head out of the water, NA or Blown :coolman:

yeah, what he said

 

[fiveo'cobra]

Here is a faq sheet on flow data of some of the most popular heads out there compared to stock E7's.

http://forums.stangnet.com/showthread.php?t=334773

As you can see, the X heads don't flow much better than GT40P's.............on the intake at least. You really need more than what they offer to have a a truely competitive car. I myself have owned a few sets of aftermarket heads. I ran a set of highly ported GT40 iron heads and after that i stepped up to some ported X heads and they felt stronger but not by much. I was sort of disappointed. Since then i have stepped up to some ported RPM's and the difference is HUGE. For the extra hundred bucks or so you can get brand new Edelbrock's instead of X heads...........deff worth the money. The only way to go on an H/C/I swap really is either AFR 165's, Edelbrock RPM's, or Twisted Wedge.

 

[JKD]

Just a side question to this, but why does so many people choose the AFR 165's instead of the 185's?

I have a S-Trim on my 93 and I'm researching which heads to buy and I thought 185's would be the way to go. Should I be looking at the 165's?

 

[Fiveoh93Snake]

Just a side question to this, but why does so many people choose the AFR 165's instead of the 185's?

I have a S-Trim on my 93 and I'm researching which heads to buy and I thought 185's would be the way to go. Should I be looking at the 165's?

Often times the 165s are chosen due to there valve size of 1.90 and 1.60 valves. That configuration allows the guys with a stock shortblock (ie. stock pistons) to run those heads without having piston to valve clearance issues. Typically the 185s with there 2.02 intake valves will have clearance issues on a stock shortblock; even more so on the 93 Cobra shortblock which utilizes 1.7RRs. AFR has also come out with an improved version of there 165 version heads; known as the 165 Comp package.

 

[~Ray~]

Here's another flow site http://www.allfordmustangs.com/Detailed/630.shtml