Well i've been looking lately and i've found a good price fro some aluminum gt-40 heads and was wondering if it would be worth it to switch form my p heads to those. i know they weigh alot less.
i say get em they will help on the weight reduction side and they flow better than the p heads too, plus you can run more timing with alum heads are they the y or x heads?
I say get them. Even if they are the Y303s they flow better than the 'P' heads. Just look at the 'sticky' on this forum. The only advantage I see in cast iron is in high boost applications (10 or more psi of boost) where they expand evenly with the block. I got the Y303s for $699. I gotta wait till next spring before I put them on though. FRPP is taking off the Y303 heads on their GT40 aluminum head long blocks and selling them as take-offs for a discounted price. FRPP is putting the new 'Z' heads on these engines along with new cams I believe.
If you comapre the GT40P and GT40Y heads, the area under the valve curves are almost ientical 9evenif the Y heads peak slightly higher), so you will only gain a weight reduction. GT40X heads will probably cost more but will make more power than the P heads on the right combo.
It looks like the gain would not be much if any at all.
Lots of work to swap the heads and consider the price of gaskets, oil, oil filter and the like. Even though you found a bargain if it was me I would save a bit more and go with heads that will give a substantial gain.
As for weight savings I can think of eaiser & less costly methods.
I'm not sure but after looking at your combo again you might gain more from a cam rather than a head swap.
Why not call one of those cam gurus and ask them what they think?
yea, after looking at it my self i can get some ebrock heads for 20% off and i was planning on doing all this when i get my new shortblock and im going to go with a trickflow stg2 cam.