Guess my horsepower - 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
  #1 (permalink)  
Old 08-15-2007, 06:04 PM
Member
 

Last journal entry: New photos
Last photo:
Join Date: Dec 2002
Posts: 182
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Guess my horsepower

What is my horsepower (flywheel and rwhp)?

1977 Corvette L48 stock bottom end

9.5-1 compression

Comp Cams 268h

Stock Vortec 906 castings with upgraded springs and machined for extra lift

True dual 2.5" exhaust without cats, magnaflow mufflers, ram horn manifolds

Stock 750cfm Q-jet carb

Edelbrock Performer RPM intake

Turbo 350 trans


Guesses?

Scott

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-15-2007, 06:16 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,658
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
I ran your combo on my Virtual Dyno Program.
Peak Horse power is 285 at 4750 RPM
Peak Torque is 364 at 2500 RPM.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-15-2007, 06:57 PM
Member
 

Last journal entry: New photos
Last photo:
Join Date: Dec 2002
Posts: 182
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
flywheel? I would have thought it much higher than that.
Scott
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-15-2007, 07:16 PM
NAIRB's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Sep 2002
Location: cimarron, ks
Posts: 1,658
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
I would peg it around 350 horsepower if it's tuned right, with over 400 ft lbs of torque.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-15-2007, 08:39 PM
Holder350's Avatar
Auto Parts Professional
 
Last photo:
Join Date: Feb 2005
Location: Whitesburg, TN
Posts: 1,037
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
you can drop 30 horses with a auto tranny, and 15-20 with a manual depending on the gear spaceing.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-16-2007, 09:05 AM
Member
 
Last photo:
Join Date: Jul 2005
Location: texas, earth
Posts: 420
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
275 at the flywheel

on a chassis dyno, mebby 235-250
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 08-16-2007, 09:19 AM
killerformula's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Carburetor
Last journal entry: Clean up
Last photo:
Join Date: Oct 2003
Location: Northeast
Age: 34
Posts: 3,485
Wiki Edits: 3

Thanks: 13
Thanked 27 Times in 18 Posts
I'd put you a little less than 300 at the flywheel, maybe 275 or so. The compression, intake and cam help a bit, but we're still looking at stocker heads and exhaust, along with a relatively mild cam.

This isn't bad considering what you're working with! Remember the 100% smogger 350's with 8.5:1 compression, smog heads, stock cams and exhaust were putting out 150-170 horse. You're a full 100 horse ahead of those motors!

K
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 08-16-2007, 10:12 AM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,815
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
Atleast 50!
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 08-16-2007, 03:19 PM
Member
 

Last journal entry: New photos
Last photo:
Join Date: Dec 2002
Posts: 182
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I found this article which looks almost identical to my set up with the exception that they spent 30minutes cleaning up the heads with a grinder and they got 384hp and 401lb-ft. http://www.chevyhiperformance.com/te..._iv/index.html
Same compression, cam, heads, and intake with a less restrictive exhaust. I can't imagine headers giving me 100hp.
Scott
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 08-16-2007, 09:09 PM
chevymastermind's Avatar
drive it like you stole it!
 

Last journal entry: engine
Last photo:
Join Date: Jan 2006
Location: tacoma, WA
Age: 24
Posts: 185
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
MY ENGINE::

350 4bolt main bored .030 to 355cid
steal crank (3.48" stroke)
Sealed power flat top -5cc flat top (9.5:1 comp. ratio)
Speed pro piston rings
Stock rods with Milodon chromoly Rod bolts
heads are chevy 333882 casting heads with a stage 2 port job
Manley Stainless steel valves 2.02int. 1.50 ex.
Comp cams roller tip rocker arms 1.6 ratio int. 1.5 ratio ex.
z-28 valve springs
Comp cams XE268 camshaft (same camshaft as you)
comp cams 84000 series lifters
Hooker headers and chambered exhaust

and on a Dyno (engine dyno-flywheel HP rating) my engine made 370.21HP @ 5662RPM and 409.1 Ft. Lbs. of tourque @ 3900RPM and it has over 400 Ft. Lbs. of tourque from 3,200-4,300 RPM!

i'd say put a aftermarket set of good flowing heads and headers on you car and a good intake manifold and you would make way more HP then you are now. or go the rought i went and bring your heads down to your local engine shop and get your heads ported! because the power band of your cam is just kicking in (2500) is right around when when your heads start flowing like crap (3500RPM)!

id put your hp at about 300-310

Last edited by chevymastermind; 08-16-2007 at 09:16 PM.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 08-16-2007, 10:40 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,658
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
He`s using Vortec heads which are the highest flowing factory head out there. Give them the correct port job and they will respond with quite a gain. When I ran his combo on the Dyno program, I used the flow chart for vortec heads.
When a engine is dyno`d for power on a gross rated dyno, it`s alot different than as in the vehicle, you have to add in the losses created by the alternator, water pump, fuel pump, fan, power steering pump, plus add in the drive train losses, after all those losses are accounted for, the number goes way down.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 08-16-2007, 10:42 PM
chevymastermind's Avatar
drive it like you stole it!
 

Last journal entry: engine
Last photo:
Join Date: Jan 2006
Location: tacoma, WA
Age: 24
Posts: 185
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by DoubleVision
He`s using Vortec heads which are the highest flowing factory head out there. Give them the correct port job and they will respond with quite a gain. When I ran his combo on the Dyno program, I used the flow chart for vortec heads.
When a engine is dyno`d for power on a gross rated dyno, it`s alot different than as in the vehicle, you have to add in the losses created by the alternator, water pump, fuel pump, fan, power steering pump, plus add in the drive train losses, after all those losses are accounted for, the number goes way down.
im not sure but im pretty sure vortecs flow better at low rpm? right?
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 08-17-2007, 12:28 PM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,023
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
Hard to fit a RPM intake under a vette hood. Do you have some kind of scope?

A 268H cam is not a ex268 cam. The 268H is 218/218 and around 0.460 lift with 110 lsa.

Headers could be hurting the power a lot. I would say at least 30hp with your setup. A set of block huggers would 1/2 the difference. Look on chevyhiperformance site. They did a story on headers. "What are headers worth?'. Yes, they lost 100hp versus stock log style manifolds but the test was done with a 292H cam (244/244 at 0.050). Your cam is much smaller and the rams horns are better than the logs so I'm thinking only a 30 or 40 hp loss.

340hp and 390 ftlbs would be my guess for crank power. I bet your car sounds good and runs strong and still gets fairly good mpg.

Any 1/4 mile runs???
with headers should be able to run 13.5's @ 103
without 13.8's at 100.
12.5's at 112 with 100hp of n20.

Dana 44 with 3.08 and a th400???

Don't worry about hp numbers so much. Are you happy with the power?

FYI, I like that 268H cam but it might be a little too big for a 3.08 gear. The 260H would feel stronger with a 3.08 and stock converter. The 268H works well with 3.40 to 3.55 gears and a 2000 stall. However, the 268H would work well with a 3.08 and 4 speed manual.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 08-17-2007, 05:36 PM
Registered User
 
Last photo:
Join Date: Jul 2004
Location: At Speed
Age: 51
Posts: 1,345
Wiki Edits: 0

Thanks: 2
Thanked 29 Times in 29 Posts
The Vortec heads will out-hp a Dart 200 up to 400hp. The Bowtie Vortecs will go 460 hp. I have built an engine like yours with untouched Vortecs, roller rockers, dyno headers 1 3/4" and an Edelbrock Q-Jet and made 340hp.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 08-17-2007, 05:59 PM
38Dodgebiz's Avatar
Gearhead for life
 

Last journal entry: Swapped out the bow-tie bling
Last photo:
Join Date: Mar 2006
Location: Chandler, AZ
Age: 53
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Less than 300. 275-285 sounds about right.
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:
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
Why I love horsepower. coldknock Hotrodders' Lounge 21 05-27-2005 11:35 AM
Horsepower.... and horsepower loss PonchoTA79400 Engine 3 03-13-2004 09:25 AM
free horsepower! minesblown Engine 3 10-05-2003 10:50 PM
302 VS 347 Really a horsepower difference?????? lakecityg Engine 12 07-13-2003 08:20 PM
Horsepower on the Target Master 350 chevylovingfarmboy Engine 1 03-06-2003 01:31 PM


All times are GMT -6. The time now is 12:21 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.