Go Back  Offshoreonly.com > Technical > General Q & A
How much HP reliably with Oval port Merlin Heads? >

How much HP reliably with Oval port Merlin Heads?

Notices

How much HP reliably with Oval port Merlin Heads?

Thread Tools
 
Old 11-14-2004 | 03:23 PM
  #1  
Audiofn's Avatar
Thread Starter
Charter Member #232
20 Year Member
Charter Member
Super Moderators
 
Joined: Oct 2000
Posts: 18,417
Likes: 6
From: Carlisle, MA USA
Default How much HP reliably with Oval port Merlin Heads?

I just got a pair of 454 motors. I dropped them off at the engine builders and he will have them apart this week I hope. What I am trying to figure out is what to do with them. They have Oval Port Merlin heads and I am wondering what is the best set up. Sould I keep them naturally aspirated, or go with blowers. I want to see mid to high 70's out of my boat (Formula 302 with a lot of lightening mods) so I will need btwn 500 and 575hp I figure so that is my goal hp wise. I know that the oval ports are better for low end grunt however can I get the HP that I am looking for with those heads?

Jon
__________________
Put your best foot forward!
Audiofn is offline  
Reply
Old 11-14-2004 | 04:52 PM
  #2  
Crazyhorse's Avatar
Registered
 
Joined: Jan 2001
Posts: 3,140
Likes: 0
From: Holland MI
Default Re: How much HP reliably with Oval port Merlin Heads?

The ones I have done in the past made 505 on the dyno, very mild 454 engines with Merlin oval-port heads. Call me if you'd like. home,616-738-0474 or cel,616-403-3962.
Crazyhorse is offline  
Reply
Old 11-14-2004 | 07:00 PM
  #3  
WAGS382's Avatar
Platinum Member
 
Joined: Oct 2003
Posts: 280
Likes: 5
From: Mentor Ohio
Default Re: How much HP reliably with Oval port Merlin Heads?

Audiofn,
I built a set of 454's with the 269cc oval port merlin's for my 311 that made 530 HP and pushed the boat to 74 MPH in fresh water.
WAGS382 is offline  
Reply
Old 11-14-2004 | 07:02 PM
  #4  
WAGS382's Avatar
Platinum Member
 
Joined: Oct 2003
Posts: 280
Likes: 5
From: Mentor Ohio
Default Re: How much HP reliably with Oval port Merlin Heads?

Here is the dyno sheet.
Attached Thumbnails How much HP reliably with Oval port Merlin Heads?-dyno.jpg  
WAGS382 is offline  
Reply
Old 11-15-2004 | 07:03 AM
  #5  
dyno's Avatar
Charter Member #655
 
Joined: Dec 2000
Posts: 4,939
Likes: 1
From: Holland, Michigan
Default Re: How much HP reliably with Oval port Merlin Heads?

The motors that Crazy is talking about are mine and SuperV's they even had flat tappet cams add a roller cam and some head work 550+......
__________________
If your boat has a sail do you ride a horse to the ramp?
dyno is offline  
Reply
Old 11-15-2004 | 07:25 AM
  #6  
Audiofn's Avatar
Thread Starter
Charter Member #232
20 Year Member
Charter Member
Super Moderators
 
Joined: Oct 2000
Posts: 18,417
Likes: 6
From: Carlisle, MA USA
Default Re: How much HP reliably with Oval port Merlin Heads?

Do you guys think those motors are maxed out? What do you guys think about dropping compresion a little and puting a blower on there?

Jon
__________________
Put your best foot forward!
Audiofn is offline  
Reply
Old 11-15-2004 | 07:44 AM
  #7  
dyno's Avatar
Charter Member #655
 
Joined: Dec 2000
Posts: 4,939
Likes: 1
From: Holland, Michigan
Default Re: How much HP reliably with Oval port Merlin Heads?

maxxed out?depends on what you mean????add a stroker crank and 40 ci you might get 30 more hp. add a blower lower the compression...600 on pump gas.
__________________
If your boat has a sail do you ride a horse to the ramp?
dyno is offline  
Reply
Old 11-15-2004 | 08:34 AM
  #8  
Audiofn's Avatar
Thread Starter
Charter Member #232
20 Year Member
Charter Member
Super Moderators
 
Joined: Oct 2000
Posts: 18,417
Likes: 6
From: Carlisle, MA USA
Default Re: How much HP reliably with Oval port Merlin Heads?

I can get a pair of blowers from the guy building them for cheap. Will have to find oval port intakes but they are not so bad from what I understand. They are the same blowers that you have Sutphen. Yes yes your trannies I will certainly need. Now I just need to save up the money again
__________________
Put your best foot forward!
Audiofn is offline  
Reply
Old 11-15-2004 | 08:38 AM
  #9  
Audiofn's Avatar
Thread Starter
Charter Member #232
20 Year Member
Charter Member
Super Moderators
 
Joined: Oct 2000
Posts: 18,417
Likes: 6
From: Carlisle, MA USA
Default Re: How much HP reliably with Oval port Merlin Heads?

Originally Posted by dyno
maxxed out?depends on what you mean????add a stroker crank and 40 ci you might get 30 more hp. add a blower lower the compression...600 on pump gas.
I want to run the crank that is in it (we are assuming it is stock 4" stroke.)

The exhaust that I plan to run is a Mercuiser/Gill set up.

Jon
__________________
Put your best foot forward!
Audiofn is offline  
Reply
Old 11-15-2004 | 09:17 AM
  #10  
Audiofn's Avatar
Thread Starter
Charter Member #232
20 Year Member
Charter Member
Super Moderators
 
Joined: Oct 2000
Posts: 18,417
Likes: 6
From: Carlisle, MA USA
Default Re: How much HP reliably with Oval port Merlin Heads?

Has to be wet due to the noise issues that I am sure that you read about Biggus and the gang up on the lake. I actually prefer wet anyhow just due to the comfort level on the boat. I just want to have fun not piss people off

Jon
__________________
Put your best foot forward!
Audiofn is offline  
Reply


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

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.