Just because you pay $2400 for custom heads does not mean your getting what you paid for or even they work correctly.
Example one of my customers came to me to the tune in his PCM that had been tuned several times by multi other tuners
I had him do a PCM OBD-II scanner recording and send it to me to analyze where I found super lean fuel trims as high as +25 lean and one head leaner then the other head.
His tuner and the shop that did his 383 LS1 to find the issues which they could not so car owner finally goes to another shop and as my request they did a compression and then leak down test to find these high dollar heads had leaking valve seats as seen below
![[Linked Image]](http://teamzr1.com/afrhead.jpg)
So think again before shelling out big bucks for custom heads where not only the vendor selling them did not know how to correctly build the heads but also the tuner who was tuning the PCM over the faults in the heads