I know someone running 10.4’s through 70 340 exhaust manifolds. I’m running mid 11’s at 117 mph through 68-69 340 exhaust manifolds. Point being you can get much more out of them then people think.

best of 11.24 at 119 mph 1.60 60’. 68 340 S Barracuda Fastback F.A.S.T [IMG]http://i67.tinypic.com/2mnnnnt.jpg[/IMG]