Does any one know

[Gamblerman02]

I have a 3.0 litre 200 hp Mercury. I have had the computer reprogramed to a 300 mod vp,Question is ,Does any one know what the difference is between the heads of 200,225 and 250 and would it make a difference to change to 225 or 250 heads.Also i didnt mention its a 3.0 200 efi Thanks for any help.

[esdbass]

They never made a 3 L 300 Mod VP to my knowledge ? I assume changing the heads as you outline would be increasing the compression. I'm no expert on 3 L EFI's but there are a bunch of guys here with a lot of 3 L EFI hot rodding experience I'm sure they'll chime in. I know it will help all of them to know more about your motor like what year it is, what boat it's on etc etc

[EuropeanAM]

Richard (kllr_bee) is the "man" when it comes to this sort of question on the EFI "mods"- he's done plenty of experimenting, and has a pretty good handle on what "will and won't work".

[Todd D]

There are 2 different 3.0l 200 efi's. Is yours the standard fishing motor or is it the work 3L. The work 3L has lower compression than the fishing 200/225/250 which use the same heads as the part/casting number is the same. 300x heads would give you more compression. It is almost impossible to find used 300x heads. Call Eric Simon his heads are cheaper than buying stock merc heads and they have the cool factor being cnc machined and anodized! Who did your computer was it Eric because to my knowledge he is the only one in the US with the capabilities. You could also add a light flywheel, popit diverter, and hydro tech tuner and make 300hp.

[Gamblerman02]

Todd,Don' know what moter it is i will have to do more research,My computer was worked by someone in N.Carolina my tech i Daytona had to sign a waiver stating it would be used for racing only.I will check casting #s on the heads and look in to Simon heads I think the motor will be the fishing motor it came on my Gambler Outlaw.

thanks