And like your saying SB a 325 C.I engine isn't making allot of velocity thru a 2 inch primary. I can't remember exactly but it's at least 2 inches

Here ya go SB, I forgot I had them in the bed of my truck.

They have a 2" Primary

https://s25.postimg.org/g2qcuwcov/image.jpg


The total length from where the 4 primaries come in to my tip 26.5" (I extended the collector all the way to the tip)

https://s25.postimg.org/i8knpeg5b/image.jpg

I added about 14" to what he originally sent me

https://s25.postimg.org/mvqpr63i7/image.jpg

Drop from the top of the collector to the bottom of the tip is 16"

https://s25.postimg.org/x732jtv7j/image.jpg

I'd be suprised if 2" as their standard bbc is 1 3/4" ID.

Edit in: beat me with above post with pics. Wow ! And...WTF ! 2"

My header gasket is 1.875" and just clears the exhaust ports in my heads. Also, my heads have had a heckuva CNC port job done on them.

LOL I know ain't that crazy! Hey Corey did you get yr sea pump braket fabbed up? I'm curious because I'm going bravo this winder and I'm trying to figure out what to do on the sea pump. I know the cp marine one is a option but thought about a crank drive to.

Yep, I ended up using a brass Jabsco pump bolted directly to the crank. Then fabbed up this bracket. I bolted it to the block where the factory A/C bracket goes. It aint the prettiest, but I didn't want to go all out till I knew it would work. If everything seems fine with it, I'll CNC a new one this summer sometime.

https://s25.postimg.org/n8gi1jghr/image.jpg

Any updates? I love this thread.

Yep, got the exhaust all dried up and looking and working the way I want it. I cut the old tails off and welded new ones on with -AN fittings inside the transom.

https://s25.postimg.org/aos16q3wf/image.jpg


Then, after measuring and remeasuring for a couple hours (and a couple of beers) I got up the courage to cut the holes I the transom for the thru-hull fittings.

https://s25.postimg.org/z6k4um6gv/image.jpg


I sealed the holes with epoxy then siliconed the crap out of the fitting and got it installed.

https://s25.postimg.org/uypclv51b/image.jpg

https://s25.postimg.org/wf0v407y7/image.jpg

https://s25.postimg.org/a5mxxgchr/image.jpg





My first real trial was this past weekend. We had the annual Checkmate Owners Rally at Lake Cumberland. I was able to put about 2-3 hours run time on her. Didn't really get on it too hard, I was mostly just checking things out and shaking it down. Everything seemed to be working pretty well. I am going to have to do some tweaking to the coolant crossover system, but that's going to be easy. Once I get a few of the little things figured out, then it'll be time to start playing!!!


https://youtu.be/MtwwjdHgAr8

cool ! glad you got it wet !!!

Sounds great !

What kind of flappers are those ?

Heck yea, sounds good !

Thanks guys!!!

The Flappers are from Hardin Marine. I didn't think it would be a good idea to run rubber ones with the exhaust being dry so those were the best option. And they don't look to hateful either.

hows it feel? how does she feel even before you get into it? can you tell a difference?

Every time I see the title of this thread "whats truly needed to swap an ls engine" I can't help but think ......

WRENCHES!!!!!!

Wrenches are needed to swap an LS engine!

The new blowup doll or the boat ? Ha !


Sorry, could't fight off the urge to say something.

Looks good and sounds great.
It doesn't sound too loud to me.

Fixed....LOL

Cruising around, surprisingly it feels about the same. Coming up on plane feels different, but I'm mostly attributing that to going to a 3 blade prop from a 4 blade, and to me babying it out of the hole.

I did get to park it next to a couple of other 253 Convincors at this past weekend's owners rally. One had a 454 mag and the other a hp500 and The back of my boat was sitting 2-3 inches higher out of the water than theirs. The one time I revved it up to about 4500-4800 and trimmed it just a fuzz, it started shooting a little rooster tail. But I did see 60 on the GPS recall, which is almost as fast as I ever saw with the stock 454. I have a 1" driver spacer as my disposal that I might try, and with the prop being so close to the surface, I'm thinking I will have to use something other than a Mirage. Lots of playing with props and drive heights in my future, but for now, she's on the water!!!

I really like seeing projects like this one!

any more pictures of the mount that you made?
I'm assuming that you have an under drive crank pulley? Any issues with fitting the pump on the snout of the crank pulley?
What did you use for the front accessories? Car or truck?
How are you liking the cam that you have now, any plans to go bigger or smaller?

Thanks

great job...the power these things make is staggering !! also if anybody is interested, I have a fresh 410ci LSX all the best stuff, eagle, crank, weisco pistons, brian tooley custom cam/valvetrain, GMPP CNC ported heads, break in only, 600+hp $6500

Great Thread! Fixing to do an LS swap in a Century!

Does the Century look like a Fountain?

If you ever have any questions, PM me. I'll shoot ya my number!!!

I did finally talk to Brent at BBlades this week. He was a huge help and made me feel a lot better about how much weight I lost out of the transom and how we can make the boat perform. His exact words were "I don't care if it comes from the nose, middle or stern, taking that much weight out of a boat is always a good thing! We will make a prop that will make it work.". He thinks a worked Bravo 1 prop is still my best bet. So I'm going to try a stock one first.

Also, one little hiccup I had was with the coolant crossover set up I was running, which was pretty much a factory setup on the front two corners only that ran into the bottom of the thermostat housing. In a factory set up it runs back into the radiator which keeps coolant flowing through the heads at all times. In my set up, the water was dead heading into the t-stat housing until the t-stat opened up. So I think I was getting steam pockets forming in the heads which is also where the temp gauge sending unit is. Cause I would get intermittent high temp readings. So now I am putting on the Trick Flow coolant crossover set up that runs all four corners and I am going to dump it into the hose that carries the water out to the thru-hull fitting in the transom for the dry exhaust. This way I will always have nice cool water running through the heads. In my head this seems like it should work. I guess I'll find out when I put it on this weekend and try it out!!!

Any new updates or other projects?

I finally got mine running really well last season. I did make a few changes though. After spending most of 2016 chasing cooling issues, I pulled the motor so I could take it apart and check everything over. When I did, I found #8 cylinder was scored. It looks like I might have sucked something in when I was fighting my reversion issues. So I ordered a new piston and rebuilt everything. This time I went with an iron block. I did this thinking the added weight (96lbs) might help me balance out the boat more and, when I took the aluminum block apart, it was full of corrosion even though the engine had at most 10 hours on it and all of those on the hose or in Lake Cumberland. I also broke down and bought the Hardin Marine accessories, but I am running them as an open cooling set up, I wish I would have done that from the start cause man, it was nice to just bolt them on, plumb it in and take off. They work awesome. I am extremely glad that I added the weight of the iron block and billet accessories back into the boat. The thing handles awesome now!!! What surprised me the most was how much better it handles in rough water than it did with the 454 in it. I was honestly thinking it would have been the opposite. Now I am in the process of playing with props. At the end of the season I was running a 24p Bravo. It was carrying the boat very well and handled great, but I wasn't quite getting the rpms out of it I wanted. So next spring, I'll keep on playing with it. But for now, here's a pic of her the last time I had it out last year at the Caesar Creek Shootout in October. She airs out pretty good!!!

https://s25.postimg.org/4czz38gen/Running_3.png

Man, looks awesome in the water. What horsepower do you think you’re getting? I’m wanting to upgrade in the next couple of seasons and thought of replacing my 350 mpi’s with LS motors but honestly will probably only need 450hp per side. I’m told my boat runs out of hull much over 80. Just not sure if the expense would be worth it over stroking my current motors.

The tune that’s in it made about 575hp on the dyno so maybe 540-550hp with the accessories on it. 450hp should be super easy out of an LS for ya.

while on this thread, if anybody is interested, I have a 408 LSX complete engine, eagle forged crank, rods, weisco pistons, GMPP CNC ported heads, ported Victer Jr. intake, BT cam, valve train, pro systems custom carb, Daytona Electronics box/harness, over 600hp om 93 email me @ [email protected] or 540-786-8111 if interested...Rob

Bringing this thread back, there is a wealth of information in it. As one of the original post questions was getting a LS based engine into a boat with a Mercruiser 5.7L I had a few more questions. I have found a 97 Bayliner 2050SS 5.7L Alpha GenII that is in good shape but needs carb and distributor among other things for less than $500. Seems to me you guys have solved most of an a LQ4 6.0L swap problems already. Trying to keep this somewhat economy swap as someone previously stated.
The Break down:
Use SBC to LS conversion motor mounts
Use flywheel from 5spd LS
3 of the 4 bolts line up but the 4 isn't exactly needed
Use Stock truck ecu can be used and converted to open loop so no 02 sensor issues with water in exhaust
Use Pleasure Craft iron exhaust manifolds and risers
Cam from stock truck LQ4 should be ok with water reversion at 114 to 116 degree LSA
Add Trunion kit for durability
Add Moroso LS Rear sump oil pan
Add electric fuel pump
Wire Harness will have to be done piece by piece using old harness and truck harness

Questions:
Use the water pump in the Alpha gen 2 and go raw water?
Interrupt switch for reverse on Alpha GenII?

I have a friend who is a LS tuner and the conversion of the ECU wont be a problem. The cooling system is where you guys get a but fuzzy. I will only be using this boat in freshwater. Some say with iron block and aluminum heads will cause corrosion with raw water and to go closed cooling and add a heat exchanger, and those are expensive at hardin marine, so is their pump. others say raw water. can you use the water pump in the Alpha and if so do you keep the stock truck water pump or put a pulley in its place? Thanks for this thread as is, as someone stated earlier there is a lot of good information and many contributors.

[QUOTE=Alwhite00;4711633]Hardin has aluminum ones but they're 1400+.

I have been following this thread for a long time. Lots of good info. I now have a 93 searay 220 BR 350/A1 and a semi low miles 5.3l with entire harness and ecu that I pulled out of a running driving truck. Attempting to do this reliable and cheap which usually dont go hand in hand. Had a few questions.
1. Are you guys using the oem gm ps pump for yours alpha? Or alpha pump?
2. Can I run dry exhaust through the alpha? As in out the prop? I wanted a captains call set up, can it be done dry or would it melt something. The pcm and harding manifolds are pricey. Was thinking of buying ls forward facing turbo headers adapt them backwards and ceramic coating them.
3. Will I have to get a sea pump? Only going freshwater. Lots of lakes in maine lol. Will the alpha raw water pump be enough to cool a stockish LS? Also, if I use raw water I then don't need a heat exchanger? Even though there's tons of room, raw water cooling appears much simpler.
thank you!

I have a sweet 02 baja H2X I love the colors but it has the 377 and it runs 60 with the family and full of gas but I want more and thinking LS

I have looked at this more than once, I actually have a couple of NASCAR Spec LS2's just waiting to be built for a boat. I figure around 10g's each to dress and install the engines, heat ex-changer, oil adapter, headers, flywheel, oil pan, engine mounts and front dress. No actual engine or ECU. I'm sure with some creativity it could be done for less.

The torque curve of the traditional SBC/BBC is better suited for a boat. A 5.3L LS is not going to gain you anything, and the cost of a supercharged LS is nuts. There have been some threads - good ones too - but you'll find that there's a lot involved in getting usable power out of them that justifies the cost. Just my thoughts.