MLS can be used on any block but some early heads had the notch. It's the heads that dictate which gasket (MLS/Graphite) that you use. 241 heads = MLS

 

Both my 01 Sierra and my 02 Silverado had 706 heads with MLS gaskets from the factory.

The graphite gaskets I believe were 99-00 only, and even then only early 00's.

 

Don't recall. That was many moons and several engines ago. I do remember when I tore it down to see what let go, it had mls gaskets.

 

Sounds like only the 862 heads have the notch.

Did they switch to 706 heads in late 2000?

 

Some 853 LS1 heads also had the notch.

 

My 01 had graphite gaskets and 862s with no notch.

 

We have seen some 853 castings have both notch and no notch, its crazy what GM will do, but I have seen this for myself...

 

I have been reading that LQ4 and LQ9 heads have the same flow #s as 243s just 6cc larger combustion chambers. So with those ls1 heads you will have more compression but less head flow.

I believe less head flow with stock cam or small cam will give you more low end tq but less top end hp/tq

Guys is this correct???

If it is then those ls1 heads are perfect for your towing needs

 

Blending the bowls and a lapping the valves is quick and easy horsepower on a set of used heads.

 

I completely agree but you definitely want to know what you are doing before attempting