I am piecing together an efi/sidemount whipple on a 454 mag.The efi wasnt all there and i think it had the vst,i have all of the cool fuel stuff. Can i just block of the other port on the fuel rail?

Yes dead head the fuel rail and use the aftermarket fuel regulator return to return back to tank

John,
We do a TON of side mount Whipples. Give me a call and I can give you a run down on the fuel system and how it should be plumbed.
Eddie
615-216-7449