540 build cam selection with gil exhaust
#35
Registered

Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
If you go with them assembled, I might suggest taking them apart, having the valve guides checked, and replacing the cheap entry level valve springs they come with. If you wanna go a little further, a sintered powder metal exhaust valve seat to replace the ductile iron seats they come with. The sintered powder metal seat is what GM used in the stock merc heads, and engine quest uses as well. If in fact, you are looking for durability, and going the distance.
#37
Registered

Joined: Feb 2009
Posts: 8,356
Likes: 1,515
From: NW Michigan
X2. I would never trust what components are actually assembled with let alone some of the shotty valve job work. I'm sure you've seen the ol man on YouTube covering all the different heads that get purchased assembled. Regardless what brand. It's to bad really. I hope you let AFR have a piece of your mind with your ordeal. I've had my problems with dart castings also but they quickly resolved with replacements. It's not just performance it's everything nowadays.
#39
Registered

Joined: Feb 2012
Posts: 4,031
Likes: 10
From: westville, NJ
a guy near me is trying to sell a 496 he had built. pro comp head dropped a valve at idle. only killed 1 sleeve, I head, and 1 piston. so he only wants 3k. this is a current day example of Chinese valves.


