and the weird noise from my engine would be??!??

[bmxmon]

I have a 65 mustang, with a 250 inline 6 with a 3spd tranny. About a week ago when i started it, it would make this weird noise. We thought it was the starter, since it was only happening when I started it. I just Put that in, and now found out it isnt that. I figured out it only happens when the clutch is in, or if you rev on the gas. Any ideas on what could be going on? Since it started making that noise, i havent been driving it, since i didnt feel like ruining my fly wheel. (i thought it was the starter) any ideas or thoughts would be great, thanks.