Bigget intake/exhaust valves to go with on 5.3 L heads
Bigget intake/exhaust valves to go with on 5.3 L heads I just recently bought a bare pair of 5.3L heads, and plan to have a local shop port them & put bigger valves in. I do not plan too mill/deck them. What are the biggest valves that I could safely go with without sacrificing power?
Most go with a 2.02, but some have been getting good numbers with a 2.05. Jay@Absolute Speed had a new development with a 2.04 valve that seemed to be doing alot of good. I'd say a 1.57 on the exaust if you plan on sticking with stock CI. Anything bigger than a 2.05, I believe, will start to shroud the combustion chamber and cause lack of power.
Launching!
Joined: Jun 2003
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From: Kansas City
Mike... Keep Me/us up to date with your heads. I too just picked up a bare set of 5.3s, and am planning on doing the same as you. I'm running a 230/230, 578/578, 112 cam, and I'm going to run the 2.05/1.57 valves. Where does one get the valves from??
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Originally Posted by Jabroni
Unless you're going to swap intake valve seats, 2.02 is the biggest you may be able to run on a stock seat.
U can get valves at almost any of the sponsors sites. Look for manleys or even better ferrea 6000's.
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Originally Posted by Jabroni
Unless you're going to swap intake valve seats, 2.02 is the biggest you may be able to run on a stock seat.
If the chambers are not properly opened up to the 3.900" bore (they are 3.800" stock) a 2.00" valve would be too big. We do these with anywhere from a 2.02-2.05 intake and a 1.55-1.57 exhaust. My car went 9's on the spray with just a 2.02 and the stock exhaust valves of 1.55
We do the CNC porting of these heads at around $699 per pair, that includes the entire intake port, exhaust port and combustion chamber. Hope this helps.
We do the CNC porting of these heads at around $699 per pair, that includes the entire intake port, exhaust port and combustion chamber. Hope this helps.
Just a little late to the party, aren't ya?
Valve sizes are mostly dependent on things like displacement, bore size, RPM, etc. A lot has changed since this thread was started in 2004, but try taking a look at what sizes some of these aftermarket heads have and pay attention to what kind of applications they're intended for. You might find a trend or at least get an idea.
Valve sizes are mostly dependent on things like displacement, bore size, RPM, etc. A lot has changed since this thread was started in 2004, but try taking a look at what sizes some of these aftermarket heads have and pay attention to what kind of applications they're intended for. You might find a trend or at least get an idea.
Also, no one is going to put forth much effort to help you out if the most you can muster is "combo is in my sig". That is a very lazy response, so don't be surprised to get some very lazy answers. I know I'm feeling too lazy to look up your cam specs, and too lazy to ask you what RPM you're turning or what port work you would do as well. Hell, I might be too lazy to respond to this thread anymore, lol.
