hp manifold vs 318 manifold

[VDART]

ok fabo' ers-- I have a 69 dart-- 318 car with stock 318 manifolds-- will any of the "a" body hp manifolds work with my saved dual exhaust pipes?
If I purchase HP manifolds will the duals I have now bolt up-- .
another question is the physical dimensions the same between 318 & hp manifolds? other than the exhaust outlet---
Thanks-- I do not want to purchase new exhaust --
Lawrence