There might be some minimal gain, probably wouldn't feel it. I say that only because when I changed mine I saw that the stock upper had some overlap on the gasket and the GT-40 had no casting flaws at all.
Either way, I wouldn't care if I lost 15 HP with the GT-40, just look at it.
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
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!