350 mag changeover

[bloodear123]

i currently have a 1988 5.7 260 hp mercruiser that is seized.My father in law has a 2004 350 mag crate motor that we are going to install but we were told that the ecm were different because i have a alpha outdrive and the one on the motor is for a bravo.we already know there is certain things we will have to change but we are not sure about the ecm.can anyone help me out with some more info.thanks

 

[newport dave]

Re: 350 mag changeover

I haven't actually done this myself, but there are a couple of guys on another board who have run Alpha's behind MPI engines that were intended for Bravo drives. They used a normally closed shift interrupt bracket/switch and wired the interrupt switch into the coil power circuit (pink/white wire connecting to the coil). They claim it works very well.

 

[bloodear123]

Re: 350 mag changeover

Thanks for the info dave it is well appreciated.Would anyone happen to know if tying in the coil with the interupt switch will cause any faults or code issues with the motor.i was thinking of bolting my shift assembly from the old 5.7 to the 350 mpi and tying in with the coil,do you think that would work i haven't looked at the switch yet to know if it is normally closed or open.i would think if it's open i could switch wires and make it closed.any info would greatly help !! thanks again