454Mag & 502Mag, Same EFI System?
 

Does the 454Mag and the 502Mag use the same EFI system? They look identical just from looking at them.

Can you replace a 454Mag with a new 502 long block and retain the stock injection system? Maybe with a ECM module from a 502 Mag?

Assuming you could make the swap how stock would the 502 need to be? Will it work for a 502/502 from GM performance?

Thanks in advance,

Ron

I think the best idea is to call Arizona Spped for any questions about Mercruiser EFI....they got all the goodies on this .

Come on guys. I cant believe no one knows about these systems besides ASM. Somebody around here has to have played with one.

Ron

"Tis often better to keep one's mouth shut and appear ignorant than to speak and prove it."

Sorry, I don't know for sure ... but I would assume at least the injector nozzles are larger just because of the displacement difference.

I heard everything was the same except ECU programming. Do a search in old listings or in tech.

I've heard it the same as Ray. You should be able to download the 502 ECM program into your current ECM as opposed to replacing. Most people charge in $300 to $400 range for this service.

The injectors are definatly different from the 454 to 502

Try going to a Merc. website like Bam. Check out the part numbers.

Part number for 454 Mag EFI fuel injector (1999 and up): 861260T
Part number for 502 Mag EFI fuel injector (1999 and up): 861260T

Last spring I had to purchase two new injectors (thanks Steve :mad: ) and I remember all the intake EFI part numbers being the same for the 454 and 502. Ray is right, all that's different is the ECU calibration. Therre are guys out there that are plenty capable of calibrating a 454 ECU to 502 specs. You should be able to get someone to flash an ECU for a couple hundred bills.

-Bayley

Thanks Bayley,

I just looked at a service manual for 454 and 502 mercruiser and everything is the same besides the ecu.

Ron