WELCOME TO RIVER DAVES PLACE

LS motor vs a 460.

farmo83

Well-Known Member
Joined
Jun 9, 2008
Messages
1,694
Reaction score
1,243
Would it be worth upgrading an old stock 460 or going putting a done up LS motor to make a CVX 20 go faster? My brother in law is inheriting my old boat and wants to go this route to kick the MPH up on it. I get parts would be more available and there would be some weight savings, how easy it would be to make an LS fit is a different story. He's thinking he can get an LS motor to around 6500 as Jets love RPMS. I'm sure it can work at some price I'm just curious as I've always been a believer in big blocks in boats.
 

Gelcoater

Well-Known Member
Joined
Sep 26, 2009
Messages
18,414
Reaction score
23,802
Would it be worth upgrading an old stock 460 or going putting a done up LS motor to make a CVX 20 go faster? My brother in law is inheriting my old boat and wants to go this route to kick the MPH up on it. I get parts would be more available and there would be some weight savings, how easy it would be to make an LS fit is a different story. He's thinking he can get an LS motor to around 6500 as Jets love RPMS. I'm sure it can work at some price I'm just curious as I've always been a believer in big blocks in boats.
Details on the engine he can get?

On a little boat like that I'd go LS any day.

Cost wise I guess it would depend on what your 460 needs? And how fast do you want to go. You know the saying;)
 

boat527

Well-Known Member
Joined
May 18, 2009
Messages
1,003
Reaction score
388
Tuff has done it with their 21, supposedly did just over 100 with the Illmor small block and an Imco Drive.. Would take some cubic dollars though..
Tuff21.JPG
 

Devilman

lol, yeah, sure, ok......
Joined
Sep 20, 2007
Messages
1,808
Reaction score
2,368
James Huff (Blazeracer on THB website) did it in his CVX20. He did it for the same reasons you mention, speed, weight savings, availability, etc... I'm not sure after all the trial & error if it ended up running any better with the LS vs. the 460 or not. It was cool that he did something different & I don't think he had a whole lot of money in it(junk yard motors, etc.) but seemed like a lot of wasted effort to me.

You could hit him up on FB if you're on there, but I found his project thread on THB if you have time to browse through it. Beware, it actually starts with some of his 460 exploits, not sure at what point he switched his focus the LS conversion and there is probably lots of extra BS to wade through, lol.

http://www.texashotboats.com/forums/index.php?topic=11838.0
 

Mark Anderson

New Member
Joined
Jun 14, 2017
Messages
3
Reaction score
5
My 460 windowed the block at the end of last season and I asked the same question. I had read a few build threads where guys had done the LS swap, but no one locally had done one or even thought it was a good idea. I had a conversation with Tom at JBP and made the decision to go for it. My 460 was a basic warmed over 9.5 to 1 motor with the usual bolt on's (cam, intake, ported heads, headers). The boat ran 65 @ 5000(b impeller). It is a heavy mini day cruiser. My original plan was to ring and bearing a LQ4 6.0l, but after some research and a lot of thought I put good rods and pistons in it. It is .005 over 10.5 to 1. I went carbed with a MSD 6014 box, Victor Jr. and 750 Holley. Cam Motion was great to work with on the cam selection. I fabed my own mounts, But JBP has rail kits. I used a Marine Power 9qt. pan and pto adapter. The problem comes with the exhaust. Marine power has a center rise manifold set. Rewarder used to make headers, but they appear to be gone. I built my own through transom injected headers. I only have a few hours on it and have not run it hard yet. On a base tune with a box stock carb it runs good. I made no changes to the pump or boat. I have made a few short full throttle bursts and the 6L turns 5800. It absolutely will pick up when I tune it a little closer.

Mark
 

jetboatperformance

Well-Known Member
Joined
Jan 1, 2008
Messages
3,655
Reaction score
4,628
Awesome ... clean install , see that u went with the heat exchanger , home it runs well for you Good job on our railkit
 

Mark Anderson

New Member
Joined
Jun 14, 2017
Messages
3
Reaction score
5
Thanks Tom! I went with the heat exchanger hoping to control the temp a little closer. I have some material coming to make blocks for the front plate. It just has 1/4 inch angle right now.

Mark
 

Nikwho

Well-Known Member
Joined
Jan 8, 2019
Messages
216
Reaction score
176
Do you run coolant in the cooling system with the heat exchanger? Would be a pretty cool deal, if one wanted to take their boat into in the winter, and didn't require nearly as much witerization! 😀
 
Top