Good luck getting the 451 to fit. .
That's another reason I like the HE351ve to HE351cw swap... with ONLY the HE351ve turbo, the HE351cw downpipe, the stock 6. 7 exhaust manifold and the aftermarket controller, you get a plug n' play swap!!! IF DP gets too high, I can add the GDP "ProGate", which is an external, boost/psi adjustable wastegate that plugs into the 6. 7 exhaust manifold where the EGR plates go (or in the case of a swap, where the delete plates go), though it does add substantially to the cost, and NON-stock appearance of the project.