I wanted to know the diffrence between the 5.3L heads. I have seen casting numbers 862 and 706 is there a diffrence?????? Can any body tell me

 

yep the 706 heads flow better

 

I think The 706's are sand casted and flow better.

 

Ive seen people using 6.0 heads. Whats different about them compared to a 5.3? larger valves?

 

We've flow tested dozens of stock truck castings over the years and when averaged out, both the 706 and 862 have near identical flow. Some are better than others due to seat lineup and core shift, but for the most part they matchup pretty close.

The 6.0l heads have a larger intake valve, different port cores and larger chambers due to the 4.0" bore they sit on.

Good luck.

Richard

 

richard.. how much would one have to "shave" from a 6.0L (LQ4) 71cc chambered
head down to a 5.3L (LM4/7) 62cc? gotta be in the .060-.075" range..
isnt that a bit to remove from a head with some sealing issues..

airdeano

 

i am buy some 706s i am planning on getting them work on what should i do to them?
milled them down 0.030" bigger valve sizes ported and polished them

 

You'll need to mill about .050" to get from 71cc to 62cc with a 317 casting. Sealing the head gasket shouldn't be a problem with n/a setups, but might be a big problem with blown applications.

Richard