LS engines are among the most common engines in custom built cars, and there are countless shops out there who specialize in them. No offense to him or you, but it's quite ridiculous to believe you can do a better job building an engine on your first try than shops like Texas Speed who have been doing it for decades with full blown R&D labs and regularly build 2000+ horsepower motors, all with highly skilled machinists and engineers using professional equipment that the average person would never be able to afford.

Edit - For reference here's a video of the shop I'm referring to. They're far from a podunk operation. https://www.youtube.com/watch?v=8HgwF5dISmU

I could do a better job than them in all due respect. I care about my job more than anyone on earth. I know they do good work but if we could both measure to the same specs and know we did it right, how could I do it worse than them. we have the same measuring tools. Not that I think they do bad work. But if you ever built an engine you know its all about attention to detail. there is nothing they have to verify the integrity of the build that I don't to a similar level of precision.

Edit: I dont have the machines they do, but when my bare block comes back from the machine shop, my tools are just as good as theirs to verify the dimensions are correct. That isn't possible to verify with a built short or long block. They could possibly have 100 employees that care as much about my job as me who knows. This is a job about verification of specs and assembling correctly not of insane tech. They don't have anything I dont when assembling an engine. Machine work yes

Texas Speed or TKM are two places I’d use if I were doing an LS build.