383 cam swap ? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 07-27-2007, 08:43 PM
383silverado's Avatar
Registered User
Last photo:
Join Date: May 2007
Location: tucson az
Age: 37
Posts: 389
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
383 cam swap ?

ok i am pulling my engine and tearing it down to inspect it for damage. i've been hearing a rattling sound at idle. and i am very concerned about this. would like to see what the heck it is

383 vortec efi

1997 3/4 ton silverado hd 4x4
csfi converted to to mpfi
383 vortec 4 bolt main
bassani headers 1 5/8 shorty's
dual exhaust 2 1/2 with high flow cats
64cc edlbrock e-tec's 170cc runner 1.94/1.55 they flow 20% more than the vortec's on the exhuast
9.8-1 compression forged pistons kb forged -18cc dished
6.0 H beam 4340 forged rods
3.75 stroke crank

current cam
the cam is a roller xr258hr 258/264 adv. 206/212 @ .050 .485/.493 with 1.52 112 lsa

cam i am thinking about getting

08-503-8 Comp Cams "Extreme" Hydraulic Roller Camshaft, 224 / 230, .502 / .510 112 LSA,High performance street machines, 2000+ stall, gears, choppy idle

my question is would it be worth the extra money to do a cam swap ?

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 07-28-2007, 05:50 AM

Last journal entry: JB's 37 Pickup
Last photo:
Join Date: Oct 2002
Location: Smoky Mountains
Age: 78
Posts: 2,358
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
You have already started mixing and matching with your semi-stock fuel injection and ECM. I think in your previous thread about engine noise, you indicated it was a MAP based controller and the OEM controller will not handle the big cam well. You will need to really talk to Comp Cams techies to get an ideal as to how much manifold vacuum you will have with this cam and compare that with the vacuum requirements for your ECM. Don't think you will like the answer because you are going to looking at big bucks for a custom ECM and from my experience, you will need to have the car available to the supplier so he can provide you with an ECM that is going to control your fuel/spark through out your expected operating range.

By the way, I watched/listened to the clip you attached to one of your previous posts on noise at idle and if did not know otherwise, I would have sworn I was listening to a Cummings. I know you are in the process of tear down and hope you looked at your valve train closely before pulling the motor. If I understood you correctly, you changed your rocker geometry. Did you check the spring clearances and the push rod length to make sure every thing was set up correctly? Don't think that kind of noise is not going to be bottom end or piston related.

Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-28-2007, 09:52 AM
383silverado's Avatar
Registered User
Last photo:
Join Date: May 2007
Location: tucson az
Age: 37
Posts: 389
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
from what i saw based on the comp cams fast flash tuner compatible cams for my 97 vortec the 08-503-8 is the the biggest cam that i can go with the stock pcm.

as for the knocking sound i took my truck to a guy here in town that builds racing engines and he said he thought it was piston #8 that had to much piston to wall clearance. i didn't ask about the cam because i didn't want to take to much of his time it was at the end of the day when i went to see him.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may post new threads
You may 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
cam for vortec 383? fiscus Engine 34 04-22-2008 08:41 PM
383 Cam Choice Help plz crusherdbuzz Engine 7 04-25-2006 04:15 PM
383 stroker block and cam ???????? mupton Engine 1 01-26-2006 09:50 PM
Should I swap myXE268 for a summit k1107 cam? 4speed57 Engine 13 07-15-2005 09:32 PM
Holley accelerator pump cam swap info/help 70bird Engine 9 07-15-2005 05:21 AM

All times are GMT -6. The time now is 07:12 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.