Go Back  Offshoreonly.com > Technical > General Q & A
whats truly needed to swap an ls engine >

whats truly needed to swap an ls engine

Notices

whats truly needed to swap an ls engine

Thread Tools
 
Old 05-24-2016, 03:45 PM
  #211  
Registered
 
Join Date: Jun 2010
Location: Central IL / Green Bay, WI
Posts: 1,119
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by corey331
Yeah, this is very true. The reason I had such a dramatic weight loss is because the engine I took out was iron block, iron heads, iron intake and iron exhaust. Now I am aluminum block, heads, intake and headers. My guess is i'm only 200-300 pounds lighter than a hp500.

On a side note, I had some reversion issues with mine when I got it running on the hose, so I had to send the headers back to Lightning to be made dry. I was told that they were shipped yesterday, so I should see them by Friday. Gonna get them installed this weekend and should be water testing very soon!!!
Good info. I love seeing real numbers...which sometimes can be eye opening. People always assume LS stuff is SO much lighter than BBC stuff...and that is sometimes the case and sometimes not.
Wasted Income is offline  
Old 05-24-2016, 04:13 PM
  #212  
Registered
 
Join Date: Oct 2011
Location: Dayton, OH/Burnside KY
Posts: 273
Likes: 0
Received 4 Likes on 4 Posts
Default

Yeah, I mean even a 300lb weight savings is pretty substantial. I think it will be even more noticeable in a multi motor application. I would love to see someone with a 283 Checkmate or 29 Fountain that has twin 454's do the LS swap just to see the weight/handling difference with the same power level.
corey331 is offline  
Old 05-24-2016, 06:15 PM
  #213  
SB
Registered
iTrader: (1)
 
Join Date: Nov 2004
Location: On A Dirt Floor
Posts: 13,550
Received 3,117 Likes on 1,403 Posts
Default

Yes, a P29 would probably be awesome as the boat was built for small blocks to begin with and was pretty fast with it's stock 320hp Merc small blocks.

Some of the smaller singlle engine sport boats can lose 3-4 mph per person added. Also gain a 3-4mph for every 20-30hp added. Win, win with the LS.

The weight loss mph help comes into play when a few hundred pounds added or subtracted makes the speedo move + or - .

I weighed a set of factory small block cast iron manifolds and risers and weighed the Eddie Marine system going on. 88lb weight loss. Great for that boat as it was one of those that lost a few mph per person added.
SB is offline  
Old 05-24-2016, 08:41 PM
  #214  
Registered
 
Join Date: Oct 2011
Location: Dayton, OH/Burnside KY
Posts: 273
Likes: 0
Received 4 Likes on 4 Posts
Default

My boat is one of those boats. The difference in the way my boat jumps on plane and runs out when its just me in it compared to when I have four people is about 7-8 mph. So the weight loss should help me out a lot there. Adding almost 300hp isn't gonna hurt either, LOL.
corey331 is offline  
Old 06-04-2016, 12:19 PM
  #215  
Registered
Platinum Member
 
Join Date: Dec 2004
Location: Melbourne Beach, FL
Posts: 484
Likes: 0
Received 0 Likes on 0 Posts
Default

Are you going to add mufflers to the dry exhaust?

Originally Posted by corey331
Yeah, this is very true. The reason I had such a dramatic weight loss is because the engine I took out was iron block, iron heads, iron intake and iron exhaust. Now I am aluminum block, heads, intake and headers. My guess is i'm only 200-300 pounds lighter than a hp500.

On a side note, I had some reversion issues with mine when I got it running on the hose, so I had to send the headers back to Lightning to be made dry. I was told that they were shipped yesterday, so I should see them by Friday. Gonna get them installed this weekend and should be water testing very soon!!!
myturn is offline  
Old 06-04-2016, 02:31 PM
  #216  
Registered
 
Join Date: Oct 2011
Location: Dayton, OH/Burnside KY
Posts: 273
Likes: 0
Received 4 Likes on 4 Posts
Default

Originally Posted by myturn
Are you going to add mufflers to the dry exhaust?
I'm going to run it and see how it is first. I have a feeling it's going to get annoying so I am looking into getting a set of clamp on mufflers. Right now I'm leaning towards the Drew Marine Shotgun's.
corey331 is offline  
Old 06-23-2016, 01:22 PM
  #217  
Registered
Platinum Member
 
Join Date: Dec 2004
Location: Melbourne Beach, FL
Posts: 484
Likes: 0
Received 0 Likes on 0 Posts
Default

Any updates?
myturn is offline  
Old 06-23-2016, 03:18 PM
  #218  
Charter Member #94
Charter Member
 
Gordo's Avatar
 
Join Date: Oct 2000
Location: New Port Richey, FL
Posts: 2,694
Received 4 Likes on 4 Posts
Default

Just curious, what LS engines are real options that are available to the public?
__________________
Abby-someone
Gordo is offline  
Old 06-23-2016, 03:21 PM
  #219  
SB
Registered
iTrader: (1)
 
Join Date: Nov 2004
Location: On A Dirt Floor
Posts: 13,550
Received 3,117 Likes on 1,403 Posts
Default

http://www.gmmarinepower.com/products.html

andthen:

http://www.gmmarinepower.com/partners.html

Last edited by SB; 06-23-2016 at 03:25 PM.
SB is offline  
Old 06-23-2016, 03:24 PM
  #220  
Registered
 
Join Date: Oct 2011
Location: Dayton, OH/Burnside KY
Posts: 273
Likes: 0
Received 4 Likes on 4 Posts
Default

Originally Posted by myturn
Any updates?
Well, I got the headers back... FINALLY!! Got it fired up and it's still sucking water in. The modification added 15" of pipe to the collector and didn't mix the water till 1/2" from the end of the tip, and it was still reverting. So needless to say, the tails are going 100% dry. No water in the exhaust stream at all. But no way will I send them back to lightning as I don't want to wait another 6 weeks for him to do a 2 week job. I'm hoping to have them back this weekend.

Here is a slow-mo video my buddy took that shows it reverting. This is with the exhaust dry to the tip. Don't mind the blue tape everywhere. I was doing some transom touch up after I cut it to fit the new exhaust.

https://www.youtube.com/watch?v=imt0LJROxtY
corey331 is offline  


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.