what's the difference between 1998 500 EFI and 1998 502?

[Maritime_Eng]

What is the difference between the two long blocks? If you took the intake system from a 500 EFI and installed it on a 502 with Stainless Marine Exhaust how close to 500hp would you get? Would the stock 502 fuel system give enough flow for the 500 injectors?

Thanks for the help.
Don

[Pat McPherson]

The difference between the two long blocks is basically valve-train.
The cam in the 500EFI has a lot more lift, the roller lifters are taller for the added lift cam, the intake valves are larger, and roller rockers are used.
I believe that the fuel system on a 502MagMPI will flow enough for a 500HP engine.
The AZ Speed intake used on the 500EFI is a little better than the Merc intake but not totally necessary for 500HP.

[cuda]

Wasn't the 98 still the carbed version?