Go Back  Offshoreonly.com > Technical > General Q & A
Mercruiser 502 / selecting the right cam? >

Mercruiser 502 / selecting the right cam?

Notices

Mercruiser 502 / selecting the right cam?

Thread Tools
 
Old 12-15-2022 | 12:15 AM
  #11  
Griff's Avatar
Charter Member # 55
25 Year Member
Charter Member
Super Moderators
 
Joined: Oct 2000
Posts: 20,242
Likes: 2,490
From: Omaha/LOTO
Default

The graphite coated gasket is OEM Merc and the other is Felpro.
Griff is online now  
Reply
Old 12-15-2022 | 06:12 AM
  #12  
Thread Starter
Registered
 
Joined: Jul 2020
Posts: 323
Likes: 55
From: Cortlandt Manor NY
Default

Originally Posted by TeamSaris
Sniper is not intended for marina use. I know they claim its USCG certified, but it isn't potted or water resistant. Spring for HP.
See I'm glad you stated that because when I spoke to Holley they told me it was and only Terminator X wasn't potted or water resistant, thank you for that conformation. In your opinion do I go to a throttlebody / multi-port injection setup or just run my stock MPI intake with HP? or toss a quality carb on it and call it a day?
Joeyboost is offline  
Reply
Old 12-15-2022 | 11:59 AM
  #13  
GPM
Registered
20 Year Member
 
Joined: Mar 2004
Posts: 2,696
Likes: 93
From: Pa
Default

Fast makes a marine ECM. It looks like you were detonating between cylinders
GPM is offline  
Reply
Old 12-15-2022 | 12:02 PM
  #14  
TeamSaris's Avatar
Driver-441
20 Year Member
Racer
 
Joined: Aug 2004
Posts: 12,011
Likes: 1,511
From: Lake George
Default

Originally Posted by Joeyboost
See I'm glad you stated that because when I spoke to Holley they told me it was and only Terminator X wasn't potted or water resistant, thank you for that conformation. In your opinion do I go to a throttlebody / multi-port injection setup or just run my stock MPI intake with HP? or toss a quality carb on it and call it a day?
I would replace the MPI intake purely for injector reasons. They are an oddball size and hard to replace. Im an EFI fan, but your budget really determines EFI v Carb.
TeamSaris is offline  
Reply
Old 12-15-2022 | 02:19 PM
  #15  
Thread Starter
Registered
 
Joined: Jul 2020
Posts: 323
Likes: 55
From: Cortlandt Manor NY
Default

If you were going to do a simple or as less complex EFI system what would you do? I just do not know what route to go? I looked into a multi-port throttle body EFI system but its a single plane intake and says from 4-7500 rpm where I need something from idle to 5,600 rpm.

I would love to ditch the stock MPI intake, I wanted to run a Edelbrock Pro-Flow XT intake but edelbrock hast shipped one in over 2yrs.
Joeyboost is offline  
Reply
Old 12-15-2022 | 02:39 PM
  #16  
GPM
Registered
20 Year Member
 
Joined: Mar 2004
Posts: 2,696
Likes: 93
From: Pa
Default

The single plane works fine in a port injected EFI application, it's not the same as a carb app.
GPM is offline  
Reply
Old 12-15-2022 | 08:00 PM
  #17  
tripps's Avatar
Registered
25 Year Member
 
Joined: Mar 2001
Posts: 2,059
Likes: 65
From: babylon,NY 11702-4116
Default Cam

No cam reccomendation?I'm in same boat,but motor is OK 30 ft bravo cmi ex
tripps is offline  
Reply
Old 12-16-2022 | 06:51 AM
  #18  
Thread Starter
Registered
 
Joined: Jul 2020
Posts: 323
Likes: 55
From: Cortlandt Manor NY
Default

Originally Posted by GPM
The single plane works fine in a port injected EFI application, it's not the same as a carb app.
https://www.holley.com/products/fuel.../parts/550-705

Not the cheapest setup when combined with HP but this is what I was thinking. Going carb would save me thousands and Dave Freiburger on Enginemasters just proved that a carb makes more power than multi-port due to the cooling effect of fuel in the intake lowering intake temps. But the AFR is not as consistent as a multi-port LOL.

I just want to know when I hit the key she fires up without dealing with pumping the throttle, flooding it or vapor lock issues.

What are your thoughts and also depending on carb or EFI does this effect cam profile? I need to start ordering parts before its spring and ****s on backorder and I'm down for the season. That cant happen!
Joeyboost is offline  
Reply
Old 12-16-2022 | 08:47 AM
  #19  
TeamSaris's Avatar
Driver-441
20 Year Member
Racer
 
Joined: Aug 2004
Posts: 12,011
Likes: 1,511
From: Lake George
Default

Originally Posted by Joeyboost
https://www.holley.com/products/fuel.../parts/550-705

Not the cheapest setup when combined with HP but this is what I was thinking. Going carb would save me thousands and Dave Freiburger on Enginemasters just proved that a carb makes more power than multi-port due to the cooling effect of fuel in the intake lowering intake temps. But the AFR is not as consistent as a multi-port LOL.

I just want to know when I hit the key she fires up without dealing with pumping the throttle, flooding it or vapor lock issues.

What are your thoughts and also depending on carb or EFI does this effect cam profile? I need to start ordering parts before its spring and ****s on backorder and I'm down for the season. That cant happen!
That or Terminator Stealth on a decent intake will be fine. For the power you're going to be making an AFR of 12.5-12.7 will be fine, the fuel distribution will be plenty good enough. Cam depends on a lot of things. If you're using wet exhaust you need a 114 LSA. An hp500 cam would be a great candidate if going hyd roller.
TeamSaris is offline  
Reply
Old 12-16-2022 | 09:14 AM
  #20  
Thread Starter
Registered
 
Joined: Jul 2020
Posts: 323
Likes: 55
From: Cortlandt Manor NY
Default

Originally Posted by TeamSaris
That or Terminator Stealth on a decent intake will be fine. For the power you're going to be making an AFR of 12.5-12.7 will be fine, the fuel distribution will be plenty good enough. Cam depends on a lot of things. If you're using wet exhaust you need a 114 LSA. An hp500 cam would be a great candidate if going hyd roller.
Its a Gen 6 block and already a hydraulic roller so I am keeping it that way. I have been debating dry tip VS wet exhaust I'm not sure I want to give up the silent choice exhaust as well. When I spoke to Comp Cams they suggested a 112LSA if I stay wet exhaust so now I'm confused. I feel like I'm in the mud with bald tires going nowhere with this build LOL.

If I were to go dry-tip exhaust how much more rowdy can I get with the cam and is it really that much louder over wet?
Joeyboost 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.