O.k. so I might be getting a good deal on some new ls6 heads and I want to put them on my 5.3. I know I will need new bolts and gaskets. How much would I need to mill to get the compression back up and see some gains. I planning on installing these and a Comp 212/218. By the way, these are the real deal sodium filled exhaust valves and hollow intake valves. What are the advantages of having the sodium filled exhaust valves????

 

Where would .030 get me as far as compression? To much? not enough? I run 93 octane.

 

Anyone?

 

Pure Sodium metal(Na), which is what is used in sodium filled valves, melts at 97°C or 207°F.
The sodium metal melts and sloshes around inside the exhaust valve. The liquid sodium metal transmits the heat from the valve head up into the valve guides. Basically just to help cool the exhaust valve.

Hollow valves are simply lighterthan solid valves. A lighter valve means a lighter valvetrain. A lighter valve train means there is less mass to accelerate and decellerate which allows for less sp[ring pressure to keep the lifter roller on the cam lobe. Generally lighter means less stress and more rpm capability all else equal.

peace
Hog

 

i talked to several machine shops and they told me it was a waste of money to use 243 heads on the 5.3..the combustion chambers are so big that it will be hard to get your compression back. And if you did have the heads milled enough to get the right compression, your intake ports wont line up causing a hp/tq loss. OR you could use a set of 4.8 flat top pistons to bump up your compression ratio. As for the lighter valves hog is right on the money. The only disadvantage is that they aren't as dependable as the solid valves. you gotta make a sacrafice either way

 

4.8 pistons and 243/799 heads are what the new 5.3's have. I'm happy with the way mine runs.

 

Are you kidding me? rofl

 

What?? Intake passages won't line up, that doesn't sound right. Haven't there been people who have done this several times on a 5.3 or am I mistaken???????? If the newer 5.3's have them how are they working and mine would not?? Just trying to find out for sure before I purchase some heads. thanks

 

Its .030 of an inch, and the heads are at an angle yet so the intake will line up fine, id have to run the math but but almost shur a .030 mill gets you back to the same size chamber as the 5.3, maybe even a tad smaller. However im not to shur if doing all this would be worth the money, your looking at 200 bucks for bolts, gaskets, and a mill on top of the price of the head and the laber.. My guess is you would gain 10-15 hp cause all u gain is a little air flow, nothing compared to a ported head.

 

Put in that cam with ls6 springs and spend the money on a Circle D 3200 converter..

You'll love your truck!!!