bolting on X-heads to my 340, can i use my exhaust manifolds?

Not real familiar with the street avengers. The accelerator pump must start squirting the moment the throttle moves. I believe the it is adjustable through different cams. The vacuum secondaries may be slow or to fast. I believe they are adjusted by canister springs. Dollars to donuts it's in one of those not the intake. If the intake was a huge single plane maybe, but not the air gap dual plane.