Hi, The 5 cyl. LS3 head in this video is one of two of LS3 V10 cylinder heads I‘ve built. Both the LS five- and LS six-cylinder heads are classified as “weldments.” A “weldment” is two or more parts welded together to create a single part.

I built two five-cylinder LS3 cylinder heads for the XR10 LS V10 project. This XR10 V10 is on the cover of the excellent 2026 Feb,/Mar. issue of Race Engine Tec. magazine.

In the early 2000s, G.M. built a LS3 V10 engine R&D project. These two five-cylinder heads duplicate those original LS 3 V10 cylinder heads.

The LS six-cylinder head is a test head. I built the LS six-cylinder head first because wanted to be sure that we could correctly weld two cylinder head halves together. This first six-cylinder LS cylinder/V12 head is .007″ too long.

I adjusted my fixtures. Then I built two V10 five-cylinder heads. All surfaces on both LSV10 and the LS V12 head are machined flat. Less than .010″ of material was removed to clean all surfaces on all three cylinder heads. Both five-cylinder V10 heads pressure test to 125 psi. One five-cylinder head is .004″ too long. The second five-cylinder head is .002″ too long.

The six-cylinder / V12 LS cylinder head will fit on the Chevy 235/292 straight six-cylinder engines. I’m sure I’m able to make cylinder heads for the Ford 300 Big 6. I can also build twin cam Ford V10 heads. What can we build for you?