i just put on a holley 4150 670cfm street avenger on my dads vette and when i started it up it was making this horrible noise and it seems like its coming from near the secondarys and i think it might be vacuum related, i have no idea, btw its got an edlebrock performer air gap intake on it, as far as i know everything is on there correctly the timing is slightly off but the car starts up

A powerful whistle, mainly at idle, fading under load/ revving?
That would be a vacuum leak, through a gasket, most likely at the base.

Thats what i was thinking there is a vacuum port and it it coming in contact with the bottom of the fuel bowl and i think it is causing the rear of the carb to not seal completely