454 mag(carb) to EFI conversion
 

I have the opportunity to buy a merc EFI setup that came off a 330hp 454, I can get the computer, injectors, and plenum--SP for a great deal, but my motor is a 1992 454 Mag and I know the heads are different. My question is there any way to make this work, Can I have the ECU reprogrammed? Are the injectors the same on the 330 as the 385hp? And can the plenum, SP, be used at all??
Thanks in advance for the help!
TC

Re: 454 mag(carb) to EFI conversion
 

I am pretty sure the intake will match up. The differences between the mark IV and mark V blocks was in the valvetrain and the coolant holes of the deck surface and head. The intakes would still bolt on. You might have an issue with the injectors though. Depending on how many LBS/HR the injectors are rated at, they may not be able to keep up with your current motors power rating. If you dont end up using the EFI set up, let me know if you want to sell it.

Pat

Re: 454 mag(carb) to EFI conversion
 

Pat, thanks for your help, I have had some tell me it will work and some tell it won't.... I have called Merc customer service and they had no clue! Surely someone on the board has tried this before...
thanks again
help needed!

Re: 454 mag(carb) to EFI conversion
 

Doesn't the 330 have the small oval head and the 385 have the rectangle head. May need to do some port matching.

Re: 454 mag(carb) to EFI conversion
 

Find who made the EFI system--a lot of them came from Arizona Speed an d they are great at technical support.

http://www.azspeed-marine.com/fuelinjection.html

Re: 454 mag(carb) to EFI conversion
 

Yes, the 330 does have oval and the 385 has rectangle, There is an intake between the plenum and the heads, I know I could get a new intake for my heads but I still don't know if the plenum and injectors are the same... thanks again

Re: 454 mag(carb) to EFI conversion
 

Thanks-
I called AZspeed&marine and they advised me to take some pics and sent it to them.. I plan to do that, I called merc cust support and they didn't have a clue.... thanks for tha help!

Re: 454 mag(carb) to EFI conversion
 

If the manifold fits the rectangle heads or can be port matched, the injectors should be fine. You may have to turn up the fuel pressure a few pounds for the extra hp.

Re: 454 mag(carb) to EFI conversion
 

I believe that injectors are only 22lbs/hr? So they need to be changed, at least. There is some useful information of the fuel injection guidelines in the following link.
http://www.holley.com/HiOctn/TechSer...l/Artcl07.html

Re: 454 mag(carb) to EFI conversion
 

I've got a 1994 454 mag carb, what does it have in it, oval or rectangular?? I was thinking of converting to mpi's as well and was curious as what changes would have to be incorporated.