Horsepower.... and horsepower loss - Hot Rod Forum : Hotrodders Bulletin Board -- 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 03-12-2004, 08:09 PM
Registered User
Join Date: Jan 2004
Location: U.S.A.
Posts: 7
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Horsepower.... and horsepower loss

Power Question:
Okay, I have a 1979 Pontiac Trans Am (it had the 403 motor in it originally). Right now I have a 1968 Pontiac 400 out of a Gran Prix (the good motor) I also have the number 16 heads (again the good ones), and an Offenhauser low rise single barrel carb intake manifold. I am planning on building the motor from scratch with all new parts. My goal is to get around 400 to 450 hp and 400 to 450 lbft at the wheels, but the power has to go through a th-350 trans with the B&m transkit (and shift kit) and a rear end with Auburn gear posi unit and richmond 3.73 gears. How much engine horsepower am i going to need to get me to those numbers, and what percentage of power will i lose through the drive train? P.S. I want to keep the stock bore and stroke, that is very important to me.

Cam Question:
same car and all that from above but i want a cam that will give me awesome low and mid-range power but also a decent high-range. I would like to stay with a hydraulic flat-tappet lifter but with roller rockers. I found a few cams from the more common companies but i like to divert from the crowd so I looked at Isky and of course they were very impressive.

Any help with answering these three questions would be greatly appriciated I'm starting to get stressed out about hitting those numbers.

Thanks to everyone and anyone who can help me,

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 03-13-2004, 01:31 AM
bullheimer's Avatar
NEVER use credit cards!

Last journal entry: car with tt2's, (stockers going back on)
Last photo:
Join Date: Jan 2002
Location: North of Seattle
Posts: 2,749
Wiki Edits: 0

Thanks: 35
Thanked 21 Times in 20 Posts
dont think you'll ever get that kind of hp to the rear wheels as you'ld have to have like 700+ at the flywheel.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-13-2004, 02:40 AM
Last photo:
Join Date: Dec 2002
Location: D.C.
Posts: 1,447
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
No he would probably have to have around 550HP at the flywheel, maybe not even that much if he was going for 400-450. Some easy answers would be using a tranny which takes less power to turn, mainly a 200-4R, you can even view the read up on the hi performance TH200

Also just read a write up on royal purple lube freeing up alot of HP and torque, thats another thing to try.

Other than that, getting those numbers out of a regular hyd. cam engine would mean you'll have to bump up the compression a bit and use a more aggressive cam which will kill your low end.

But with out switching to a roller cam, or going toward a blower, it's hard to get to those numbers. My friends blown cobra only makes 380HP and 400ft lbs. at the wheel with a kenny bell attached.

If you wanted to gain back some low end power you could switch to a dual plane manifold at the sacrifice of a few top end numbers. Just an idea.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-13-2004, 10:25 AM
Registered User
Join Date: Jan 2004
Location: U.S.A.
Posts: 7
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
the Offenhauser intake is a dual plane manifold and it's going to be pushing about 10.5:1 to 11:1 compression
Reply With Quote Quick reply to this message

Recent Engine posts with photos
Gear in this thread - Powered by O'Reilly Auto Parts

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

All times are GMT -6. The time now is 02:24 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2015, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright 1999 - 2012. All Rights Reserved.