Merc 5.0LX

[osueric27]

I have a 1995 Sea Ray 215 EC with a Merc 5.0LX Alpha One. It has been well maintained and runs great. However, I would like to know if there are any performance upgrades I can do to the engine such as electronics or airflow which may give me a little more horsepower. I have tried several different props and get the best performance from a Vengence SS 17 pitch. It gets on plane fairly quick except when I have several people on board. I cruise at 3000RPM at about 27 to 28MPH when loaded. Top end is about 45MPH at 4600RPM which is what the specs say. Since I have found the optimal prop that works best for the boat now, I am wondering what options I have to add some gains to the engine without sacrificing reliability.

Any suggestions would be very much appreciated.

Eric

 

[Limited-Time]

Re: Merc 5.0LX

Best upgrade dollar for dollar is to go to the 5.7. All you need is a long block ($1800.00 to $2200.00 depending where you buy it from)and a place to change out the engines. All the bolt ons from the 5.0 will fit right on the 5.7 block. It may require a different intake and carb, but its the best $for$ performance you can buy. I'm sure you'll be able to sell the old engine to recoup some cost.

 

[riverjet502]

Re: Merc 5.0LX

I agree with the post above...Pull the 305 out...Sell it to someone looking for a lawn mower engine. Not really worth the cost to try and hop that little V-8 up.. Much more cost effective to run a 350 or better yet run a 383 (Stroked 350) It's a cake recipe anymore for a 400-425 hp 383 these days...Very very reliable and extremely torquey.. Deffinately will put a huge grin on your face... Plus your outdrive will survive the power increase with no problem...

 

[osueric27]

Re: Merc 5.0LX

Where is a good place to buy a 350 or 383? Should it be a reman such as Jasper engines?

 

[riverjet502]

Re: Merc 5.0LX

What I did when I repowered my jet. I went through the parts books and then talked to the machine shops about pricing for machining a seasoned block. Then I started looking at the local chevy dealers. GM has hellish pricing on their crate motors. They say that they aren't for marine use. The head gaskets that came on my 502/502 were stamped from GM "For marine use" Go figure?? I did change the valves to inconal. swaped to a high volume oil pump. 10 qt molidone marine pan. The cam that came with it works good for my exhaust application. A bigger cam would be even better. I couldn't build a motor for $5200 with all the hard parts (forged) that came with this crate. This engine is a good foundation to build more power. Do your homework and take your time. I have 7 seanson now on my motor and it runs hard yet and has given me no troubles. I have since spoken with several people who have been using GM crate motors in there boats with just minor changes. I was told by the dealer who I purchased my motor from that a local manufacture has purchased several 502's from them as well.