Hi, Please take a look at my LS V10/V12 Cylinder Head Weldment Video.
The A.W.S. classifies 2 cyl. Heads welded as one, to be a “weldment.”
G.M. started a L.S. V10 R.&D. Program in the early 2000s. The project stopped in 2008.
A few die hard Chevy people bought the 8 LS V10 test engines. Darren (LS Brackets) bought 2 engine blocks and 1 pair of LS V10 Cyl. heads.
I built two five-cylinder LS cylinder Head weldments for Darren’s 2nd (G.M.) V10 engine block.

These are 2 LS V10 Cyl. Head Weldments. They are assembled and ready to bolt on

The S six-cylinder/V12 head weldment is a test. I built the LS six-cylinder head first. I wanted to be sure we could weld two cyl. Head halves together. My first 6-cyl. LS 6 Cyl./V12 head is .007 inches short.

I adjusted my fixtures. Then I built two V10 five Cyl. Head Weldments.
Less than .010″ of material is removed to machine surfaces on the three Cyl. Heads.
Every surface on the LS V10/V12 Cylinder Head Weldment is flat.

The 2 LS V10 halves welded and machined. The stock valve guides were not removed or bored.
The valve on the left side is on the left side Cyl. Head “half”. The valves on the right side are in the right side Cyl. Head “half”.
We need a .003 inches “feeler gauge” to make the 5 valve” stems” perfectly align.

One five-cylinder head is .004″ too long. The second five-cylinder head is .002″ too long. Both five-cylinder V10 heads pressure test to 125 psi

I can make the 6-cyl./ V12 LS cyl. Heads fit on the Chevy 235/292 STR. 6-cyl. Engines. I’m sure I can make Alum. Cyl. Heads for the Ford 300 Big 6. I can build twin cam Ford V10 heads.

Race Engine Tech. Magazine Feb./March 2026 issue has a cover story on Darren’s LSXR10 Project.