Cam for a Vortec 355 - Page 2 - 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
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #16 (permalink)  
Old 10-16-2012, 12:20 PM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 26
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
What do you guys think about the nostaliga cam from comp cams I listed?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 10-16-2012, 01:15 PM
Registered User
 
Join Date: Oct 2011
Location: Mo
Posts: 148
Wiki Edits: 0

Thanks: 0
Thanked 6 Times in 6 Posts
Thise old factory grinds belong in a museum with 8 track tape players and stromberg carbs. I hope I don't sound snotty or anything but cam science has changed a lot in the last 10 years, embrace it.
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 10-16-2012, 02:13 PM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,125
Wiki Edits: 0

Thanks: 17
Thanked 335 Times in 315 Posts
[quote=hpete;1599643]
Quote:
Originally Posted by ap72 View Post
Of the cams you listed the xe274 is the best. If you insist on using that cam the Vortec heads would really bennefit from a good valve job and porting.[
A good valve job that includes 2.05 intakes, 1.6 exhausts, swept chambers and enlarged bowls
no. 1.94/1.6 valves. Using larger than that is just going to cost you, your peak flow is limited by the pushrod pinch in the runner, taking it all the way out will allow you to effectively run 2.02" valves but more than that is going in the wrong direction.
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 10-16-2012, 05:10 PM
Registered User
 
Join Date: Oct 2011
Location: Mo
Posts: 148
Wiki Edits: 0

Thanks: 0
Thanked 6 Times in 6 Posts
ap72 I don't agree. Although it would be better to fully port the heads along with the bigger valves, they'll still flow better even at lowlift with pocket porting and bigger valves. I would agree that 2.05's may be overkill for the application they won't hurt anything and at least here in the states 2.05's don't cost any more than 2.02's. If I stayed with 1.94's I'd be very careful who I let touch the seats.
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 10-16-2012, 06:24 PM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,125
Wiki Edits: 0

Thanks: 17
Thanked 335 Times in 315 Posts
Quote:
Originally Posted by hpete View Post
ap72 I don't agree. Although it would be better to fully port the heads along with the bigger valves, they'll still flow better even at lowlift with pocket porting and bigger valves. I would agree that 2.05's may be overkill for the application they won't hurt anything and at least here in the states 2.05's don't cost any more than 2.02's. If I stayed with 1.94's I'd be very careful who I let touch the seats.
They won't flow any more and your coefficent of discharge goes to ****. bigger valves are NOT always better.
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 10-16-2012, 08:05 PM
Registered User
 
Join Date: Oct 2012
Posts: 5
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
I have the extreme energy hydraulic cam. 274 in my 69 Nova SS 355 very close to your set up and it euns very well I'd go with 274 if your looking to drive often.
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 10-16-2012, 09:23 PM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 37
Posts: 806
Wiki Edits: 0

Thanks: 92
Thanked 60 Times in 50 Posts
I have read that adding larger valves to Vortecs is bad because it decreases intake charge velocity. Also the casting is pretty thin and close to the water jacket and cutting for larger valves increases chances of a crack developing which is also a factor that needs consideration when porting Vortecs. The intake flow numbers for Vortecs are pretty awesome. They are lackluster in exhaust flow, so if you port, do the exhaust side.
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 10-16-2012, 09:56 PM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,153
Wiki Edits: 0

Thanks: 5
Thanked 380 Times in 374 Posts
Xe274H-10 needs 4.10's for that car.

Xe274 or 12-672-4 cs nostalgia 30-30h+ or Isky 278 mega cam
All these cams will need 4.10's. a 3500 stall is best with all a these.

3.55:1 use a smaller cam .

12-672-4 This cam will be particilarly lame with just 3.55's.
Needs a 3500++4000 stall and 4.30-4.56

You must fully port a vortec heads to see the benefit of a large than stock valve.
Larger valves and full porting will work well.
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 10-16-2012, 10:15 PM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,122
Wiki Edits: 0

Thanks: 324
Thanked 785 Times in 751 Posts
how are camshaft profiles related "directly" to rear gear ratios? An engine doesnt run any different in a boat and their "gearing" is totally different?
Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 10-17-2012, 04:35 AM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 26
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
I have a np440 gearbox laying around, do you guys that would be better then the th350?
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 10-17-2012, 06:29 AM
Registered User
 
Last photo:
Join Date: Jan 2011
Location: Hopewell, Va
Age: 62
Posts: 1,208
Wiki Edits: 0

Thanks: 0
Thanked 118 Times in 114 Posts
Cam for a Vortec 355

Quote:
Originally Posted by M.Rydell View Post
Hello! This is my first post here.


I'm just woundering what cam will be the best for my engine. Car is Camaro 69 with a th350 with 3000 stall and 3,55 gears. Vortec heads 10:5.1 cr Air gap intake quickfuel 750 e85 headers
Xe274 or 12-672-4 cs nostalgia 30-30h+ or Isky 278 mega cam

thanks alot for the help!
Cheers from Sweden!
Your Vortec heads basic operating range would benifit with a cam like this. Lunati 301A3LUN - Lunati Hydraulic Flat Tappet Camshafts - Overview - SummitRacing.com The heads don't have anything left after 5500 rpms. It would also improve them with bowl blending and mild porting.
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 10-17-2012, 07:31 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,125
Wiki Edits: 0

Thanks: 17
Thanked 335 Times in 315 Posts
Quote:
Originally Posted by Silver Surfer View Post
I have read that adding larger valves to Vortecs is bad because it decreases intake charge velocity. Also the casting is pretty thin and close to the water jacket and cutting for larger valves increases chances of a crack developing which is also a factor that needs consideration when porting Vortecs. The intake flow numbers for Vortecs are pretty awesome. They are lackluster in exhaust flow, so if you port, do the exhaust side.
Their exhaust flow really isn't "lack luster" when compared to any other OEM castings, and the fact that they don't have a exhaust crossover is a huge plus. They're way down compared to an aftermarket head, but no bad for a stock as cast OEM head.
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 10-17-2012, 07:34 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,125
Wiki Edits: 0

Thanks: 17
Thanked 335 Times in 315 Posts
Quote:
Originally Posted by vinniekq2 View Post
how are camshaft profiles related "directly" to rear gear ratios? An engine doesnt run any different in a boat and their "gearing" is totally different?
They aren't related directly BUT what F'bird is getting at is that with a 26-28" tire size and a 1:1 final trans ratio those rear gears and stall would help put the operating band of the engine closer to where the cam causes it to make most of its power. If you move your power band up then you need steeper gears to make your car run at that RPM.

Changing gears is not totally necessary but in most cases it enables the driver to make the best use of the new found power at the higher RPM ranges.
Reply With Quote Quick reply to this message
  #29 (permalink)  
Old 10-17-2012, 07:48 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,122
Wiki Edits: 0

Thanks: 324
Thanked 785 Times in 751 Posts
AP72,you are correct"They aren't related directly"

most cars and trucks have multi gear transmissions,to say a car with a flat tappet hydraulic cam "needs" 4.30 or 4.56 gears?
Im trying not to correct or call out anyone,but,,,,,,,?lets think about gear choices and applications.I use 3.5 gears and my cam is 256/264@50 with valve lift over 600,is my gear choice wrong?
Reply With Quote Quick reply to this message
  #30 (permalink)  
Old 10-17-2012, 01:16 PM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,153
Wiki Edits: 0

Thanks: 5
Thanked 380 Times in 374 Posts
Quote:
Originally Posted by vinniekq2 View Post
AP72,you are correct"They aren't related directly"

most cars and trucks have multi gear transmissions,to say a car with a flat tappet hydraulic cam "needs" 4.30 or 4.56 gears?
Im trying not to correct or call out anyone,but,,,,,,,?lets think about gear choices and applications.I use 3.5 gears and my cam is 256/264@50 with valve lift over 600,is my gear choice wrong?
Not of you are running bonneville. Or have a very high horsepower to weight ratio.
On the street you will have sluggish initial acceleration with a big cam and no gear. ( assuming typical car wight and HP to weight ratio).
You will also be "on the converter" for a long time when you rug it.
Inefficient, creates converter heat. Long wait for the power band to hit.
Bad choice when a high stall converter is used (unless the power to weight ratio is very high)

Unless your car is very light weight or your don't care about acceleration.

Of course if you have no tires traction It won't matter much.

You average camaro malibu muscle car #3200-3600# with a 350 and a 256 cam and 28" tall tires wiill want a 4.30 to 4.56 gear It wil alos want 10:1 to 10.5:1 cr (for pump gas)( if you want strong acceleration.)
The motor will want to cruise at 60MPH at around 3200-3400rpm in Drive (1:1)

At the track you would be way under geared with 3.50:1 gears. Your ET will be 4 to 8 th's slower than what It could be with the right gears.

You can run what ever gear you want in your car. Its your car. But don't expect stong acceleration performance with a big cammed 350 and hiway gears in a typical weight car or even worse in a heavy truck) and a stock low stall converter. All the torque power will be at higher rpm ...very high vehicle speed. Initial Acceleration will be lame untill the rpm gets up to where
the cam makes power. 3000+++ 3500++rpm for a racey 256 cam.
Unless you got 5 or 6 transmission speeds (with a low 1st and 2nd ratio) to work with. Not the typical 3 forward gears and a 2.5:1 first gear as in most cars.
If you want to optimize it to break the land speed record thats a different thing.

Last edited by F-BIRD'88; 10-17-2012 at 01:44 PM.
Reply With Quote Quick reply to this message

Recent Engine 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:
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
Help with picking roller cam for Vortec 355 zildjian4life218 Engine 82 06-07-2012 09:06 AM
Final tuning of my vortec headed 355. zildjian4life218 Engine 42 08-07-2011 04:38 PM
Roller vortec 355 build questions 1986c10 Engine 17 06-03-2011 12:16 PM
355 w/ vortec heads abas_abas Engine 11 03-24-2009 05:54 AM
How would you build a 383? A 355? Vortec or package deal? Adrenaline_Fiend Engine 5 04-29-2003 07:58 PM


All times are GMT -6. The time now is 07:50 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.