Stock 502 EFI engines
 

I am sure this question has been beatin to death on is board, however I am new at this marine stuff and just purchased a 35 lightening with 2004 stock merc 502 EFI. Is there any simple upgrades available to boost HP. I have been told be careful because some of the internal compnents may not be able to handle any extra power. They are suppose to be 415 HP from factory. Any info would be great.

Thanks

Re: Stock 502 EFI engines
 

Aluminum Heads Larger Cam New Exhaust.

Re: Stock 502 EFI engines
 

Headers are a great place to start.........mild cam etc.......

Re: Stock 502 EFI engines
 

Something like a set of headers from Stainless marine ?

Re: Stock 502 EFI engines
 

call mark at precision marine 504 469 7463 he is the top efi man and can tell you in very short time what would be your best and safest mods.

Re: Stock 502 EFI engines
 

Thank you , I will call Mark today.

Re: Stock 502 EFI engines
 

If I'm not mistaken, wasn't the Merc 502 discontinued when the 496 was introduced in 2001?

Re: Stock 502 EFI engines
 

The best "boost" is BOOST! Add some HP manifolds, and slap on a couple of Whipples, and you got yurself one fast boat! :eek:

Re: Stock 502 EFI engines
 

In my opinion, the vortech is the best system on the 502MPI. You will have 700HP and depending on how you run it, you will still have reliability. If you go the extra mile and beef up the valve train, you will really have something.

Re: Stock 502 EFI engines
 

Also, Any mods you do will have to work in conjunction with the computer for that engine. Tyler Crocket has an excellent up-grade package for the Merc 502MPI that includes surfacing the heads, larger stainless valves, valve job, roller rocker arm conversion, hydraulic roller cam upgrade, CMI headers and computer mods---good for about 100hp per engine........or you can go with a Vortec supercharger kit or something comparable. Either way it will cost THOU$AND$.

Re: Stock 502 EFI engines
 

That was my first thought.........
A local had a 1999ish Baja with a fresh 502 in it. He bought a 2004 Nordic and swapped motors before he sold the Baja. Someone got the 1999ish baja with a new 496, while he kept the motor he liked in the boat he wanted.

Re: Stock 502 EFI engines
 

I think the last year for the 502 was 2002.

There are no decent "bolt-ons" for the 502 if you want to keep the EFI.

The kit Kamma spoke of from Tyler is a great kit but it's about $6k per engine. I have heard nothing but good things about Vortech superchargers for the 502 but again about $6k. It would be nice if there was something out there that was "in-between" for a couple thousand that would get you 40-50 TRUE hp!

Re: Stock 502 EFI engines
 

The 502 CID (8.2L) Mercury engine is still in production; Mercury Racing's 525EFI; 600SCI and the 700SCI are all using the 502 block.

Re: Stock 502 EFI engines
 

Sorry, I meant the last year for the 502 MAG EFI motor that we are talking about in this thread.