Re: Can 5psi be reliable on a non-magnum 454?
 

Isn't the fuel system on the MPI's inadequate for that?

Re: Can 5psi be reliable on a non-magnum 454?
 

I'll be damned...learn something new everyday!

So more or less a 454 mag w/ factory SC...

Re: Can 5psi be reliable on a non-magnum 454?
 

Think of it as a "Mag Plus". ..better valves etc ect...

Re: Can 5psi be reliable on a non-magnum 454?
 

454 Mag injectors will work, not sure if a 7.4 MPI are the same. You need to upgrade fuel delivery to an Airomotive fuel pump larger lines and dump back into the tank as an open fuel system.

Re: Can 5psi be reliable on a non-magnum 454?
 

More than that.

Low comp ratio pistons, bigger cam, roller rockers, Gil or CMI exhaust depending on year and expensive blue paint. Also hand assembled and balanced at Merc Racing.

Great turnkey engines. Mine has 470hrs on it with the top end freshened at 350hrs.

Re: Can 5psi be reliable on a non-magnum 454?
 

are the HP525SC motors running square or oval port heads?

Re: Can 5psi be reliable on a non-magnum 454?
 

Square heads. It's basically a Merc 420 with TRW dish top pistons.

Re: Can 5psi be reliable on a non-magnum 454?
 

I think the fuels sysyem would be the biggest worry,make sure you don't cut costs there!!