Hello,

I have a 1968 gto with a pontiac 455 removed from a 71 goat i beleive. I just put a new holley 750 carb on it, and I drained my oil to find a gallon of gas in the oil as well. It never did that before when I had the old carb on so I was just wondering if it could be something with the carb, I just hope it aint what im expecting it to be. Please let me know, thanks!  

Assuming you haven't swapped to an electric fuel pump when you put the Holley on, I think the problem is an over-rich condition flooding the motor. Have you checked the float levels? With the engine at idle and the sight plugs removed, fuel should be just at the bottom of the sight plug threads, bouncing the fender slightly should make fuel slosh out the plug holes. If its running out, adjust the float level down (loosen the lock screw slightly and use a wrench to turn the adjuster nut clockwise then retighten the lock screw) and try again.
If that isn't it, try this- idle the engine for a few minutes and shut the engine off, before it dies open the throttle and hold it open, use a flashlight (not a lighter!) and look down the throttle bores to se if any fuel is dripping into the manifold. (Don't shut it off then open the throttle later- you will definitely see fuel from the accelerator pump!) If you do see fuel it may be as simple as the float bowl bolts loosened off and needing to be retightened-but not too tight, they are small threads in aluminum.
If you did install an electric pump without a regulator, or with the regulator set at too much psi, you may cause flooding due to the fuel pressure pushing the needle and seat open against the float level- lower the psi.