496 mag ho

Old 12-29-2019, 08:23 AM
Thread Starter
Join Date: Aug 2010
Location: Streamwood IL.
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
Default 496 mag ho

We have a 2002 Powerquest Vyper and we are having our 496 Mag Ho's rebuilt. They are replacing with steel crank, forged pistons, new roller rockers, oil pump, valves, head work. Also replacing the exhaust header to CMI Etop headers.

This is were i am not sure what direction to go. Do we keep the cam stock, or one step up from stock? I don't want to go with too big of a cam. If we go with a bigger cam we have to get the ECM's re mapped. The person doing the work has a dyno and will remap the ECM's when running on the dyno.

I still want the reliability of a stock engine but more performance,

Still up in the air about changing from a stock cam and remapping the ECM's.

Anyone already go through this? Please provide pros and cons.
Any issues afterwards?

Any help and insight would be appreciated.
Thank you,

Last edited by mcr vyper; 12-29-2019 at 02:16 PM.
mcr vyper is offline  
Old 01-03-2020, 12:19 PM
Join Date: Feb 2012
Location: Omaha, NE
Posts: 222
Likes: 0
Received 2 Likes on 2 Posts

You are spending the money for forged crank and pistons as well as headers, yet questioning cams and re-program ECM's? If you are going to leave stock cam, why bother?
Cory H is offline  
Old 01-03-2020, 01:12 PM
iTrader: (1)
Join Date: Nov 2004
Location: Lago Vista TX
Posts: 895
Received 28 Likes on 12 Posts

Originally Posted by mcr vyper View Post
. The person doing the work has a dyno and will remap the ECM's when running on the dyno.

Very FEW can tune the PCM 555's

Mine (on 525efi's) were done by datalogging and sent back and forth UPS a few times to Mark Boos
Boatally Insane is offline  
Old 01-03-2020, 01:13 PM
Join Date: Oct 2010
Location: Hemlock, MI
Posts: 809
Received 18 Likes on 13 Posts

So why exactly are you rebuilding motors?

Factory crank in that motor is modern cast nodular iron-same material as new LS motors and is plenty strong even for some moderate HP increases. Weak part of rotating assy. was the cast pistons which had too small of valve reliefs for much bigger cam than stock and weak valve springs as well.

Stock heads and intake are very limiting on that motor. Raylar is mostly the only aftermarket for that motor, Dart makes a couple things now. BoostPower (Alexiz) likes modding that motor and does it well.

The 496 exhaust manifolds were actually very goof from the factory and you will likely see zero or minuscule gains for dollars spent on CMI e-tops over factory manifolds.

Who is doing the work on the motors?
Gimme Fuel 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 - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.