GT40 Y302 heads vs GT40P heads

[stevesLX]

I just picked up a set of Aluminum GT40Y heads and I am going to put them on and take off my GT40 P heads. Will these heads flow better than the 40P's? Will I be able to tell a difference or is this going to make the car a pooch. With the 40p's on there the car pulls super hard from idle thru 4th gear. I am hopeing the car will pull just as hard or harder with the GT40 Y's

 

[ninety15.0]

the y's do outflow the P heads....just not by a ton. Plus they are going to be a hell of a lot lighter and b/c they're aluminum you could probably run some more timing.

 

[samickguy15]

X2

 

[2000xp8]

I had a set of Y's.
Do yourself a favor before you put them on, take them for a valve job, bowl cleanup, and spring seat pressure adjustment. Y's and X's certainly aren't known for their good factory valve jobs.
Ya, it's another $200 you don't want to spend, but it's well worth it.
With the work i described and proper other supporting mods you should be able to come in just shy of 290rwhp. (seen it, just not on my car)
No numbers from mine, i went to TW's.

 

[Jack's95gt]

I ran them both. The y heads I believe are 62cc combustion chambers compared to 59cc for the p heads. You'll lose a little compression ratio but you can run more timing. overall they are a nice upgrade.