I have a 223ls with a 454 330hp, thinking of converting to a 502 efi. Anyone have any thoughts, or have done this? Is it even worth it? Will it be too much power for the hull?

Go for it. If you get a drop in motor it will be a piece of cake. You will have to watch your speed and your steering as one thing that you may need depending on speed is external steering.

Jon

Dave, I did a similar project conerting my old 420's to 502EFI's great upgrade very reliable power with good performance. I also closed cooled mine to add life.The only tricky part is the bellhousing conversion. I also recomend changing wiring harnesses with the engines. Are the 502's used, I dont know that Merc is still making them? I did mine in 2000 they told me mine were last sets they were building before going to 496's. those would be a great engine for that boat also. If I can help at all email me with your number and I'll call you. Good Luck, Mark B.

Dave,

I am not sure how far along you are, but believe it or not I am working on the same upgrade!

I did not see an answer on the hull/ hp question. Have you or does anyone have any concerns there?

With the 502 I would like to mount the motor better to the stringers, have you come up with a way to get a better mount in that hull?

I am in the process of replacing my 330 hp. 454 with a built up 454 mag motor (around 470 hp.) in my 1989 223ls. I am using Mercuisers offshore motor mount which runs across the stringers (I think it's used on HP500's etc...). It's around $185 from Mercruiser but is non adjustable once set in place. I noticed my stinger is a little fatiqued around the stock mount on the drivers side, so I will be doing some fiberglass work and sandwhiching it in aluminum. As for the hull, most people tell me external steering is a must because the 223 will start to Chine walk at much over 62-64. I'll probably go with a WPM single ram. I know I may be a little overpowered for the hull, but it's fun none-the-less. I am also curious if anyone has run big HP. in a 223.

Dave and Scott,
I have a 223 that used to have a 330HP 454.It was replaced last spring with a fresh 454/425 Merc (TRS motor). It's also got Gil offshore exhaust and a bigger Ultradyne cam.I'm thinking it's about 470/480 HP.I talked to the guy that had the boat when it had the 330 in it and he said it ran 62 (speedo) with that motor.When he had the new engine put in, he saw 72 (speedo). 10 mph gain!

I bought the boat in Dec., Only got to go out twice.Once was the seatrial in which the boat ran good enough for me to take it home.The boat saw 72 on the speedo 68.7gps @ 5200, 44mph @3500, and 52mph @4000. This was with a 23P Hydromotive 4blade.You have no idea how bad i'm itchin to get out on the water!

I got a 25 Mirage plus over the winter and will post the speed/rpm's if it ever warms up.One way or another I WILL see 70 on the gps!

Craig,
I think we have very similiar setups. Are you running external steering of any type? I am on the fence right now if I want to shell out the $1300+ for external steering. Think I might just as a safety precaution. Did the boat Chine walk at all over 60?

I should be getting my motor back from the builder this week. Also running a Ultradyne cam, CMI exhaust and Merlin heads. Builder says I should be around 470+ h.p.

I think you'll find the boat will run over 70 with the 3 blade. That is the same prop that I was going to try. People I know that have the same boat (one friend with a 380 - 400 hp. small block) say that the boat responds better to a three blade. Let me know you results once you try it. Curious if I'm in the ballpark with a 25P Mirage Plus.

Hi Scott, and Craig. The 470 HP should spin the 25 plus fine I ran the numbers and at 5000 RPM with a 1.5 ratio and allowing 10% slip the boat should run just over 70 mph.Also make sure you get the alignment right on bfore you start drilling holes on those racing brackets. I changed mine to Aluminum brackets made of 1/2 inch alum welded gussets and then 4 stainless 1/2 inch bolts on each one.And used the adjustable ones that came new on the 502's. Mostly because I had trouble when I pulled my engines for service they were off a fraction every time they went back.
good Luck Guys, MFB

DJW I tried emailing you back a couple of times check your address.

Scott,
I'm not running any external steering. I've talked to a bunch of people about that and the ones who want me to buy it from them say it's a must have! Everyone else says that its not needed at my speed however it may save some wear and tear on the steering components. I'm not getting it at this point.

Now remember that I've only been out twice, But the boat handled great , no chine walk at all. No slide in the turns whatsoever and jumped right up on plane.The prop guy said that the Hydromotive props provide more stern lift. He also said that I should get more speed out of the Mirage Plus due to bow lift, but you never know until you try. I'm sure it'll be a different ride. I'll post the results.


Craig

Craig223,
I run a hydromotive on my 242 perfect cruz prop lot of bow lift, & quick plane. Which one are you planning on getting? I lost some top end when I went from my 3 blade to 4 but hell I rarely run extended open for long periods anyway. But with alot of fuel and bikinis on board who cares as long as you look good doin it.

Rocket