i have a 1968 camaro 350 with 4 speed and yada....im thinking this could be a exuast leak but when i first take off in any gear its makin a funny noise, like vibration noise almost but once i get on it or get over 2-2500 rpms its goes away but if i back off the gas and get back on it its has the same vibration noise for like 3 seconds and goes back away...car seems to be running fine and all just when i give it gas thats why im thinking its some type of exuast leak but i have fount no place it could be leaking and i tightned up all my header's and such