Go Back  Offshoreonly.com > Technical > General Q & A
Best option for 5.7 Mag exhaust replacment? >

Best option for 5.7 Mag exhaust replacment?

Notices

Best option for 5.7 Mag exhaust replacment?

Thread Tools
 
Old 05-19-2010, 10:31 AM
  #1  
Registered
Thread Starter
 
Join Date: Mar 2010
Location: Belleville, MI
Posts: 89
Likes: 0
Received 0 Likes on 0 Posts
Default Best option for 5.7 Mag exhaust replacment?

Hey Guys,

I've got a 1990 Scarab 21' with a 5.7 Mag. I've noticed a small crack in the water jacket of one of the exhaust manifolds, so I'm looking to replace the set. Does anyone have any experience with the cheap re-pops out there?

Thanks
-Rob
RivMan is offline  
Old 05-19-2010, 07:49 PM
  #2  
Platinum Member
Platinum Member
 
ChristianGott's Avatar
 
Join Date: Nov 2000
Location: Connecticut
Posts: 1,397
Received 10 Likes on 5 Posts
Default

try this...

http://www.perfprotech.com/store/pro...-NS,75402.aspx

i'd do the cheap manifolds, but go with imco or another quality ss riser...
ChristianGott is offline  
Old 05-19-2010, 08:59 PM
  #3  
Registered
 
Expensive Date's Avatar
 
Join Date: May 2006
Location: West Creek NJ
Posts: 4,227
Received 1 Like on 1 Post
Default

I just put the Imco Thumper setup on my boat.It was reasonable about 1k a motor and came with everything.
Expensive Date is offline  
Old 05-19-2010, 10:36 PM
  #4  
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha/LOTO
Posts: 19,558
Received 1,821 Likes on 907 Posts
Default

I would take a look at Revolution marine exhaust.
Griff is offline  
Old 05-20-2010, 02:09 PM
  #5  
Platinum Member
Platinum Member
iTrader: (2)
 
TomZ's Avatar
 
Join Date: Feb 2001
Location: Virginia Beach, VA
Posts: 3,983
Received 1,234 Likes on 688 Posts
Default

I have used GLM aluminum manifolds with very good results. The internal passages are a split design (separating the exhaust pulses) and the aluminum shaves about 50 lbs off the stern. I paired these these with a set of Hardin/IMCO stainless risers. Very good results... I have about $500 in the whole set up (I bought the risers used).

Tom
TomZ is offline  
Old 05-20-2010, 05:19 PM
  #6  
Registered
 
Join Date: Feb 2001
Location: Tortola
Posts: 130
Likes: 0
Received 0 Likes on 0 Posts
Default

tom z did you see any difference in performance with the glm manifolds. any gain in rpm. thanks.
cigarette39 is offline  
Old 05-20-2010, 08:38 PM
  #7  
Registered
Thread Starter
 
Join Date: Mar 2010
Location: Belleville, MI
Posts: 89
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks for the ideas guys!

I think I'm going to end up picking up some factory Merc manifolds.

I see 2 options, ceramic or E-coat.

Merc's site says Ceramic for salt, and E-coat for fresh, is this correct?

Thanks
-Rob
RivMan is offline  
Old 05-20-2010, 11:08 PM
  #8  
Platinum Member
Platinum Member
iTrader: (2)
 
TomZ's Avatar
 
Join Date: Feb 2001
Location: Virginia Beach, VA
Posts: 3,983
Received 1,234 Likes on 688 Posts
Default

Originally Posted by cigarette39
tom z did you see any difference in performance with the glm manifolds. any gain in rpm. thanks.
I couldn't tell you. I picked up the boat sans power and built a 383 for it. It was turning 5300-5400 RPM and running 77 on GPS. I have other friends with small block power running the same setup and approaching or surpassing 80. I'd say they work.

Dennis Moore (Small Block and Big Block Marine Performance book author) is behind the design on these.

I have a new cam from RMBuilder going in this weekend. Hoping to add another 800 RPM or so. The exhaust is more than capable of supporting it.

Hope this helps.

Tom
TomZ is offline  
Old 05-21-2010, 12:25 AM
  #9  
Registered
 
Join Date: Feb 2001
Location: Tortola
Posts: 130
Likes: 0
Received 0 Likes on 0 Posts
Default

thanks tomz let me know how the new cams work.
cigarette39 is offline  

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



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.