qwiketz

Hi all,

Hopefully some guys who have done this can chime in. I'm taking a look at ordering a new boat without the engine. My thought is that if I am buying a boat that I'll have for 15 or 20 years, and that sbc based engine is going to be even further behind tech wise by the time I sell it. The tech or lack thereof annoys me already, so I'll definitely at some point do the swap, so I am thinking I might as well do it now. The upgrade to big block is roughly an $8000 upgrade cost off the base engine and weights about 400-500 lbs more fully dressed than an aluminum ls or lt.

If I have my own engine built or buy a basic lt1 engine from marinepower:

http://marinepowerusa.com/engines/6-...6-base-engine/
then I can use the hardin marine serpentine and cooling kit:
https://www.hardin-marine.com/p-7408...3-and-ls6.aspx


They have engine mounts listed are:

https://www.hardin-marine.com/p-1043...lications.aspx

So, my question is, besides exhaust manifolds, what else do I need?

Also, marine power offers "drop in ready" engine replacements, so maybe they include all that I need?

http://marinepowerusa.com/engines/6-2l-di-enpac/

I'll probably have to call them as I can't tell the difference between their sport pac and eng pac packages. The descriptions are almost the same.

gnx7

iTrader: (28)

I would build a motor and use the marine style paint on all metal surfaces like boat manufacturers do.... 6.2 with an LSA blower would be great! Even a 6.0 would be fine. People are selling their LSA blowers now as a bigger version is out now boasting 1000rwhp out of the box.... the LSA blowers peak out around 800rwhp or so. The marine power exhaust manifolds cost more than the motor I had! https://ls1tech.com/forums/conversio...efi-power.html

I used a motor from a truck... aside from painting the block we didn't really paint much else. It was used in fresh water all the time though. I found that all aluminum parts over time would corrode a small amount.... but had I of clear coated them they probably would not have... or painted them like the block. Boats require maintenance annually and if you don't do it (we didn't hahaha) things degrade slowly over time. Each spring when we took the boat out of hibernation (outside covered in tarps) the motor was a little more corroded.... but a quick touch up with spray paint and some light sanding made it look a lot better. I noticed the coil pack holders rusted each year.... the rest really wasn't that bad. I had a MarinePower alternator that took a crap after 1 year.... then put on one from a truck we had and it lasted 4+ years. The starter was a Marine Power style though. My n/a engine was fine.... but a blower would've made it soooo much better.

qwiketz

Thanks for reaching out. I read your thread on your build and it was great.

if I don’t buy a ready to go solution, I may build the motor. This is especially true if a company sells an install kit of sorts with all the brackets and marine specific stuff to install (I’ve been spending some time on the Hardin marine site).

i was thinking a lt1 would be nice because I can probably get away with a little bigger cam and not have issues to to the reverb of the water cooled exhaust due to the variable cam. I would like to stroke it up if I can keep the oil squirters. If so, everything would be forged and I may eventually add the stock 1.7 take off supercharger since they are so cheap. I want the lt4, but $30k is a lot for the drop in motor. Even the ls9 is $22k. My budget is more like 10-15k and it takes about $6k for all the boat specific stuff.

is there anything fancy or unique that need to be done/bought to get the car engine to mate up with the bravo one or is that the easy part? Seems like it shouldn’t be hard?

by the way, I know you’re a big forced induction guy and so am I but even the prospect of going from 300hp to 420 while loosing 200-300 lbs sounds great. The upgrade cost is $8 or $9000 to go from the 300Ho 6.2 up to the 502 / 425 hp. That also adds about 400-500 lbs versus the ltx/lsx.

qwiketz

Also, really interesting comment about the exhaust crossover. Never really thought about it since you don’t see it on the boat forums.

showdog75

iTrader: (8)

Wonder if a Mercruiser Alpha would handle a LS? It has a GM 3.0 litre 4 banger in there now.

qwiketz

Keep in mind an alpha is the lowest on the totem pole. If you baby it, it’ll work but you can shred that thing if you really get on it out of the hole.

im looking at a fully built Teague drive because even the bravo would require some babying to get it to live long term

qwiketz

Gnx7, you wouldn’t happen to know if the pricing on the website for stuff is accurate or with an account if it gets much cheaper would you? The lt1 engine setup is roughly $15k and the lsa is $22k. They don’t have the lt4 yet but that will likely be around $30k.

timharber

I think you'd be miles and hours ahead buying it ready to roll and then doing the swap or look for them to install an LS based power plant.

I'm going to have my Baja big blocks replaced with twin 441 LS based engines with blowers and the parts list is amazingly long and I haven't even gotten into the drives or electronics yet.

I also don't know how the boat will handle with the weight reduction. All that's calculated in the hull design and how it will plane, so lots to think about.

Best of luck! Who are you buying this boat from?

Tim

qwiketz

Hey Tim,

who’s doing you’re setups? Any more specs and rough costs?

i was thinking of going with one of the marine power setups (lt1, lsa or lt4 once it is available). It’s just easier than knit picking every thing and having to piece it together. It’d be nice if there was a laundry list of parts required but I haven’t found one yet.

i was looking at the used market but may end up buying new after all.

im looking at the west coast style powerboats. I’ve looked at cobra and they up till now have not offered anything other than mercury.

tahiti offshore will do virtually anything you want and they have done a 24’ skier with a lsa. I have a call into them. There’s a bunch of video on their Instagram. They did a 23’ deck and it was 85 mph + with a stock lsa.

as a car guy, no matter what brand I go with, it’ll have a ls/lt based motor at some point. More power, less weight and more rpm band.

the lsa is roughly $22k and 560 hp and the lt4 is 620 hp in marine trim for roughly $30k. The question becomes whether the Additional 60 hp, stronger block and updated technology such as direct injection (for better or for worse) are worth the money.

anyone know if the lsa has the variable cam timing? If not, that may be an advantage of the lt based engines since you may be able to run a cam that acts smaller at idle and larger on the top end (benefit due to reversion or water getting sucked through the exhaust into the engine)

G Atsma

LSA does not have VVT or AFM/DOD.

qwiketz

thanks!

they both have the oil squirters which will be good for the sustained rpm and load.

Cfoss

I put a pair of LQ4s in my boat. Thread is here:

https://ls1tech.com/forums/introduct...how-i-did.html

I have heard not great things about marinepower. Hardin or Kodiak is the way I would go if I bought from an engine manufacturer.

The alpha would probably hold a stock ls for a while. Upgrade the cam and forget about it, unless you have a REALLLY slow throttle hand.

There are some threads at scream and fly site, but few and far between.

Bob Madera (Sp?) is supposed to be the marine cam guy. I left mine stock.


Chay

Derek48

Hey I’m looking into this too I have a line on a 2015 6.2 truck engine and I wanted to buy it to put in my regal with bravo 3. Is there anything specific with that year I should look out for? Upgrade lifters or anything else?

Cfoss

I'm no expert on the valvetrain aspect.

I will say that if you upgrade the cam sometimes it requires different springs to accommodate the extra lift.

Usually these upgrades are to get the engine to breathe into the 6500 rpm range which is not typically desired in marine applications, other than race applications. There is not a lot of information on this type of usage.


I suspect that the 6.2 is a VVT engine, and should provide more torque on the bottom and midranges.

Mine are gen3, and simple fixed cams.

Good luck with your project.


Chay