i just recently did a build up on a 350 it has a edelbrock 1406 carb on it and a accel hei ignition with vaccum advance

the problem is i bought the pickup with a 400 sbc in it with those items on the engine
THen i build my 350 and stuck em on the engine with no changes but now i have no vaccum coming out of my carb that hooks up to my vaccums advance. the other side which goes to my tranny has tons of vaccum can some please help

thanks