Truth on the 4 banger stuff. We just built a 2010 Camaro for a customer and with a very basic build (stock bottom end but heads and cam done) the car put down 675whp with 7psi from a TVS2300. Really impressive for not a whole lot of money spent and a stock bottom end! (Vid is on my YT channel)
And cool on the machine shop, just happened to be coincidence then with my guy saying he does that at the same time. Yes, he does CNC work tho. I send him some ACAD drawings I make for adapter plates and other items, he punches them right out. Quick turn around and reasonable on the price. I listed his name and shop name above, tell him Nick from GT sent you, he'll help you out if you need!