regalman4925

I have been researching the option of running a LS based motor in my 89 Baja sport 250. currently I have a 454/roughly 450hp and have been collecting parts for a stroker build shooting for 600hp. lately I have been seeing allot of LS stuff in boats and it has me really debating a attempt at one. i believe a base 5.3 is something like 325hp which would be equivalent to a 330 minus some weight. allot of guys are reporting 500hp with a cam swap and mild head work. if that is achievable then i would think another 50hp+ and the reduced weight would likely help my boat out a bit. i have a feeling i would be heading in the direction of boost if the motor happened to work out well. from what i have gathered the exhaust is the most expensive hurtle to get over money wise, about 1500 gets you a pair of aluminum manifolds brand new. i can find a 5.3 or 6.0 in the local salvage yard complete for 200-300 depending on who is working, sometimes the guys don't charge extra for accessories. from what i am reading you can swap out the AC pump with a sea pump and use the factory serpentine setup. i already have a external fuel pump from a holley efi setup laying here and would have to run a return line on the fuel. one thing i am not sure on is the oil cooling system, i certainly would think you need a cooler of some sort but i have not read about anyone saying what they used. right now i am thinking i would retain the factory EFI setup and i have a friend trying this same setup in a 22' crownline that is ordering the tuning software and knows enough about tuning to get running. bellhousings match standard bravo, flywheels are 100 new, motor mounts can be bought cheap or i can even fab my own. am i missing something here? does anyone have any links to other people doing this? i have read about allot of different boats from little jet boats to a 32 skater but have yet to see a 27 single engine. i think i can do this for a low enough price that its worth the chance of it not working, i can always throw the LS motor in one of my cars and sell the manifolds to someone else trying to same type of thing. thoughts?

COOPS

I will be following this one. I bought a 292 with the 6.2's and love the boat. I wonder what it would do with a set of LS based motors in place of the 6.2's.

regalman4925

I would think twins at that size would do awesome! I am thinking that even if I don't gain a single mph I would be running lighter and more fuel efficient and have the potential for more power with boost or spray. From everything I read a stock lower end can handle 700hp which would more than keep me happy if I can even come close to that. another awesome thing to consider is i can walk into a salvage yard and find LS engines and parts all over the place. I could have a extra motor on hand at all times in case I blow one up for a minimal amount of money. I am thining about doing this in stages, I may try 100% stock 5.3 or 6.0 and see what it does in the boat, then swap in a cam and see what it does and then depending on how it works I may try to boost it after that. my buddy and I were looking at water cooled turbos, that is a very possible thing to do.

Budman II

Have you seen this thread?

http://www.offshoreonly.com/forums/g...ls-engine.html

If not, it will provide some interesting reading. The LS is a stout platform that has the potential for some serious performance.

regalman4925

yea i read it once and now reading it again. the oil cooling still seems to be once of my biggest questions. I am thinking that I can use the stock AC location to fab up a plate to hold a stock sea pump but I need to look at the brackets first to see. part of me is thinking I may be better off going carbed for now but it seems that allot of people that went carbed said they would have rather stayed efi. its cheaper for me to run stock efi since it will come with the motor. I would have to rewire the harness and adapt a BBC or similar harness to helm which should not be a issue. I am really thinking that this can work, and I think it would have enough power to move my boat. if it doesn't I will still have my BBC sitting on the bench ready to drop in and throw the LS in another project.

Blueabyss

Just use the stock EFI. Only thing you might need is an aftermarket ecu.

FIXX

on a boat that size i would look into going bigger,,like getting a 6.0 or a 6.2 to gert that heavy boat on plane..you will need torque and the smaller cid ls engines dont have as strong bottom end torque as a BBC..i my eyes you would need to add some cubes in order to come close to the 600 hp target number you really want..like mentioned use the stock efi and get a holly dominator ecu and wireing and go have fun..

Wes Burmark

We have a stock 5.7 in our 2002 Corvette. Oil temps runs 190 - 240 in the Vette so I believe an oil cooler would be needed for marine applications.
I think twin 427s from my Z06 would make great LS engines for my 29' Fountain!

Borgie

Having owned a ERL 370ci 1,200 hp turbo LS, I can agree they are indeed engineering marvels to say the least. However, for the money it's hard to beat the torque of a BBC. If you could incorporate turbos or a supercharger, then sure, would be really cool. For 600hp naturally aspirated, no way.

Gh700xx

600 n/a would be doable but you're talking 454lsx at least to get there and even then it might be a little high strung for a marine app.