Go Back  Offshoreonly.com > Technical > General Q & A
too much small block ? >

too much small block ?

Notices

too much small block ?

Thread Tools
 
Old 06-28-2007, 03:35 PM
  #1  
Registered
Thread Starter
 
Join Date: Jan 2006
Location: canton IL
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
Default too much small block ?

My brother is building a 20 foot open bow EBKO boat and bought a best friends 355 SBC out of his drag car. Well time and funds don't allow allot of changes to the motor yet and so he wants to put it in and go boating for the rest of the summer . But it has 12:1's and a cam with 578 lift and 260 degrees of duration . Some say that you have problems with reversion but also some say that is you extend the center outlet a few more inches towards the transom it will work .Any input there?
scorpion king is offline  
Old 06-28-2007, 04:14 PM
  #2  
Registered
 
PatriYacht's Avatar
 
Join Date: Jul 2002
Location: Waterford,MI
Posts: 2,867
Likes: 0
Received 1 Like on 1 Post
Default

Does he have enough money for a new set of tailpipes? Most likely it will revert and then he will have to change back to the old engine or put dry tailpipes on it. Also 12 to 1 compression will require race gas. I wouldn't do it.
PatriYacht is offline  
Old 06-28-2007, 06:07 PM
  #3  
Registered
 
Join Date: Feb 2003
Location: Vice City & Tavernier, FL
Posts: 5,900
Received 10 Likes on 4 Posts
Default

drag engines spike the rpms for a very short period of time....marine application will have that engine at high rpms for extended periods....probably will not last.....will most probably have reversion at idle and definitely will require race gas....not good idea
thedonz is offline  
Old 06-29-2007, 05:31 AM
  #4  
Gold Member
Gold Member
 
Iggy's Avatar
 
Join Date: Jan 2001
Location: Kissimmee, Florida
Posts: 4,155
Likes: 0
Received 2 Likes on 2 Posts
Default

The torque curve of a drag motor is too short and peaks way too late to be of use in a boat. Marine engines should have as flat a torque curve as possible.
Iggy is offline  
Old 06-29-2007, 07:01 AM
  #5  
Registered
iTrader: (1)
 
Join Date: Jun 2004
Location: Omaha, Nebraska. Boat on the Mighty Mo! Longest river in the USA!
Posts: 1,944
Received 37 Likes on 23 Posts
Default

What are the Idle Characteristics of this engine?
1BIGJIM is offline  
Old 06-29-2007, 08:47 PM
  #6  
Registered
iTrader: (8)
 
Join Date: Nov 2006
Location: Tygart Lake, WV
Posts: 1,290
Received 122 Likes on 83 Posts
Default

I'm assuming stock manifolds are going to be used. With that size cam it's going to revert water horribly which is going to lead to an early end to the motor. I had to add 8" extensions to my risers to prevent reversion with my small 226/230 112LSA cam. Do it right and rebuild for a marine application.
Ryan00TJ is offline  
Old 06-30-2007, 09:18 AM
  #7  
VIP Member
VIP Member
 
Pat McPherson's Avatar
 
Join Date: Oct 2002
Location: Ivoryton, CT
Posts: 5,246
Likes: 0
Received 3 Likes on 3 Posts
Default

Like everyone is telling you, swap the cam, and lower the compression...
__________________
Patrick
Pat McPherson is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
handfulz28
Formula
10
10-15-2006 02:25 PM
DKerns
General Q & A
5
09-05-2006 01:40 PM
Badtoon
General Q & A
3
12-29-2004 04:39 PM
chriscraft240
General Q & A
4
08-28-2003 01:17 PM
Da Patriot
General Q & A
44
11-24-2002 08:27 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



Quick Reply: too much small block ?


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.