First it depends on what car they're going in. There is a company that makes a shorty header for C 4V heads (and maybe 2V) in a fox mustang. I can't remember the name but I talked to them about the shorties they have when I was looking for mine. The guy I talked to said they wouldn't work for my engine because they would cost me about 150 hp on a 600 hp engine. I don't think that if you went from the best custom header money can buy to a stock manifold it would cost more than 50 hp but that's what he said. Just pm Raceallday1. He can tell you the name of the company. That's where I heard about them from.
A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, production numbers, VIN decoders, modifications, troubleshooting, power adders, DIY tutorials, and more!