Of the 3 heads, which is thickest under the valve spring pads?

 

Cut some apart and let us know.....JK
They're all GM castings; for the most part you cant machine them down any further...only larger diameter. If you need more installed height then longer valves, + up locks, or + up retainers are your only options when starting with the GM castings.

 

Thanks for the reply, but none of that info applies to what I want to do, I'm looking for information not advise.

I've heard that the LSA castings are "heavier", if true, I'd like to know where the extra material is, and how the LS3/LS9 castings compare.

 

Only someone who has cross sectionally cut them apart or made the mold patterns would know this answer for you. Aren't they all the same casting numbers anyways ?? If so then maybe GM mills them less so the deck surface is thicker for less distortion under booost.

 

I don't know, don't want to buy each head and destroy them if I don't have to. If I can't get the info then that's what I'll have to do.

 

I believe the difference is the way the lsa heads are made and the material used.

 

The LSA and LS3 are very different. There is way more material in the port in the LSA heads, and they have gussets supporting the rocker stands. Valve drop is the same between the two, so I don't think GM just mills them less to achieve a thicker deck. Unported, I'd guess the LSA has more material under the spring pad, but only because there is a lot more material around the guide boss in the port.

I'm not too familiar with the LS9 heads though.

 

The LSA is definitely beefier compared to the LS3 head, weighs more and is cast using a different process. You should call Advanced Inductions and WCCH. Both have a lot of experience with those heads and have CNC programs specifically for them; so more than likely they could give you the exact info you're looking for.

 

Good to know..I've only seen the LS3s from a 12' GS Vette; but not the LSAs
Is the IN. runner volume smaller or less CCs ?

 

Yes, the runner volume is smaller so there are less cc's. I see if I can find some pics and post them later.

 

There's no change in that specific spot where the spring seat gets thin to the intake runner. The wing in the LSA/LS9 head is adjacent to the intake valve guide.



work won't let me access any of the good LSA intake runner pictures I find to paste here for comparison. Go to google images and search "LSA intake runner wing"