1990 Chevy 350/ Just for discussion - 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> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 12-22-2010, 10:06 PM
American Muscle's Avatar
305 Turbo-Fire 240hp
 
Last photo:
Join Date: Dec 2008
Location: under the hood
Age: 31
Posts: 625
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
1990 Chevy 350/ Just for discussion

Ive read lots about the 90-94 swirl port heads being not the best heads. But I can remember growing up my dad having a 1990 chevy silverado swb. And man would this truck fly. No mods at all completely stock. He could smoke the tire all the way through second. It seemed pretty fast to me, fast enough i think to drop in a hot rod and really do some stuff. Growing up I cant recall at what rpms power dropped off but I sure loved rinding with dad and the occasional peel outs. So why are these not good heads cause they seemed awesome then.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-22-2010, 10:27 PM
Member
 
Last wiki edit: Ford axle ratio codes
Last journal entry: Rear Suspension
Last photo:
Join Date: Aug 2005
Location: Prattsville
Posts: 6,359
Wiki Edits: 31

Thanks: 2
Thanked 54 Times in 50 Posts
I can do the same thing with my '95 K1500 extended cab long bed.. has a 305 and a 5spd. 1st gear is very steep, and 2nd gear is low enough to start out in. combined with the light rear end of a truck, it's a tire burner... the swirl port heads suck, because there just not good heads.. if you look at a TBI 350, they made 200hp.. the 305 makes 160 hp IIRC...
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-23-2010, 12:43 AM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,654
Wiki Edits: 0

Thanks: 15
Thanked 58 Times in 55 Posts
There`s many discussions on these heads on other web sites. Guys claim they`ve ported them and made them work as well as Vortecs. I myself don`t buy that. My 92 Chevy truck has a well warmed up 4.3 V6 TBI, 5 speed transmission and a 3.42 posi. I can roast the 9 inch wide BFGoodrich hides off the back easy. The swirl port heads make explosive low end torque but due to the swirl vane, the mixture reaches it`s maximum velocity around 3800 RPM and afterwards it falls on it`s face because it`s giving it all it can give it, the swirl vane hampers flow past that point. To combat this issue on my truck, I did some light bowl porting and installed after market Ferrea SS necked down valves plus had a back cut put on them. I have a fully ported TBI, edelbrock performer TBI intake, Venom injectors, larger roller cam, the whole 9 yards but when it reaches 4000 RPM I can feel it stop pulling. Sure, the engine will tach to 5500, but the power drops off to nothing at 4000 RPM.
Even had I fully ported the heads, I doubt it would have did much good, when a big swirl vane is made into the valve bowl it becomes a blockage at some point. This was why in the 80`s they were named "Vortec" because a "Vortex" is a tornado, the heads swirled the mixture like a tornado, so hence the name.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-23-2010, 03:10 AM
Registered User
 
Last photo:
Join Date: Mar 2009
Location: Burton, MI
Posts: 789
Wiki Edits: 0

Thanks: 35
Thanked 15 Times in 14 Posts
i had an '86 astro van with the 4.3l and those swirl port heads..

my dad and I (He was a GM Powertrain engineer) ground those swirl vanes out completely when we had the heads off to do valve stem seals.. they flowed so much better, the engine would hardly run on the stock tune any more.

we ended up having to build a whole new fuel and spark table for the TBI and MAN did that 4.3l scream afterwards.. made TONS more power higher up in the rpm band. I never towed with it.. so I wasn't bothered giving up a bit of low end torque for the much wider useful power band :>
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-23-2010, 04:15 AM
American Muscle's Avatar
305 Turbo-Fire 240hp
 
Last photo:
Join Date: Dec 2008
Location: under the hood
Age: 31
Posts: 625
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
my brother has a 94 chevy truck with stock 350, and he can blow the tires off, but I tear him up everytime with my 86 chevy truck with a mild 305. We both have 700r4 and usually are neck and neck out the gate but my little ole "305" seems to breath a little better. Where swirl ports only on trucks, did they come in any cars of that era. The reason I ask is it is more likely for trucks to have the torquey heads for hauling.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 12-23-2010, 09:41 AM
Registered User
 

Last journal entry: Paint
Last photo:
Join Date: Sep 2010
Location: USA
Posts: 816
Wiki Edits: 0

Thanks: 0
Thanked 11 Times in 11 Posts
Quote:
Originally Posted by American Muscle
my brother has a 94 chevy truck with stock 350, and he can blow the tires off, but I tear him up everytime with my 86 chevy truck with a mild 305. We both have 700r4 and usually are neck and neck out the gate but my little ole "305" seems to breath a little better. Where swirl ports only on trucks, did they come in any cars of that era. The reason I ask is it is more likely for trucks to have the torquey heads for hauling.
They used swirl port heads on Caprice police cars. Sheesh, if you are only turning 2200 rpms at 75 mph how fast do you think a truck will be going at 4000 rpms?
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 12-23-2010, 09:52 AM
Registered User
 

Last journal entry: Paint
Last photo:
Join Date: Sep 2010
Location: USA
Posts: 816
Wiki Edits: 0

Thanks: 0
Thanked 11 Times in 11 Posts
Some of the TBI 350 truck engines were rated at 210 hp and some were 200 hp. I think it had to do with the exhaust.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 12-23-2010, 10:01 AM
Member
 
Last wiki edit: Ford axle ratio codes
Last journal entry: Rear Suspension
Last photo:
Join Date: Aug 2005
Location: Prattsville
Posts: 6,359
Wiki Edits: 31

Thanks: 2
Thanked 54 Times in 50 Posts
some had dual exhaust
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 12-23-2010, 10:16 AM
Registered User
 

Last journal entry: Paint
Last photo:
Join Date: Sep 2010
Location: USA
Posts: 816
Wiki Edits: 0

Thanks: 0
Thanked 11 Times in 11 Posts
The dual exhaust exhaust is only from the muffler back. I think they also use a different cat converter. It was sometime after 92 that the hp rating went down.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 12-23-2010, 11:11 AM
Registered User
 
Last photo:
Join Date: Mar 2009
Location: Burton, MI
Posts: 789
Wiki Edits: 0

Thanks: 35
Thanked 15 Times in 14 Posts
Quote:
Originally Posted by V8&4spd
They used swirl port heads on Caprice police cars. Sheesh, if you are only turning 2200 rpms at 75 mph how fast do you think a truck will be going at 4000 rpms?
my '72 monte carlo does 2250 rpm @ 70
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

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
1990 chevy 350 ss swags05 Hotrodding Basics 41 12-26-2012 09:53 PM
1990 chevy 5 speed streetrodderbn Transmission - Rearend 2 03-30-2010 09:20 AM
1990 Chevy van 350? Mollard Engine 9 10-29-2004 08:55 AM
1990 chevy vette dopey Electrical 1 08-24-2004 02:28 PM
1990 chevy 350??? xxx(madmax )xxx Engine 3 03-10-2003 06:10 PM


All times are GMT -6. The time now is 12:54 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.