350 sbc - 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 08-22-2012, 03:19 PM
Registered User
 
Join Date: May 2012
Location: Central Iowa
Age: 19
Posts: 41
Wiki Edits: 0

Thanks: 6
Thanked 1 Time in 1 Post
350 sbc

What is the easiest and cheapest way to add a little power to a stock 350 sbc in a 1971 Chevelle?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-22-2012, 03:51 PM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 7,840
Wiki Edits: 0

Thanks: 313
Thanked 750 Times in 721 Posts
headers and exhaust/manifold and better carb next
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-22-2012, 03:54 PM
Registered User
 
Last photo:
Join Date: May 2009
Location: S/E Michigan
Posts: 653
Wiki Edits: 0

Thanks: 0
Thanked 9 Times in 9 Posts
Install a small nitrous kit, one that goes to 125hp max. As long as your engine is in good running condition now, adding a 100 shot (per manufactureres instructions) will not harm your motor.

A full dual exhaust(headers, pipes, performance mufflers) could gain you about 20-30hp

Changing the rear gear ratio(depending wht youu currently have), can also add some more performance for less than a grand, but nitrous is still the best bang for the buck.
Reply With Quote Quick reply to this message
The Following User Says Thank You to FmrStrtracer For This Useful Post:
Vberg (08-22-2012)
  #4 (permalink)  
Old 08-22-2012, 04:07 PM
Registered User
 
Join Date: May 2012
Location: Central Iowa
Age: 19
Posts: 41
Wiki Edits: 0

Thanks: 6
Thanked 1 Time in 1 Post
I'm trying to convince the kid that has the car to let me put nitrous on it but hes afraid it might hurt the motor....I'm pretty sure its never been rebuilt (50,000 miles I believe) but it still runs good so is it still ok to use? Sorry I've never used it before so I don't know much about it...
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-22-2012, 04:10 PM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 7,840
Wiki Edits: 0

Thanks: 313
Thanked 750 Times in 721 Posts
low shots of nitrous is ok. It feels like you opened the 4 bbl on the lowest setting.needs good plugs and ignition
Reply With Quote Quick reply to this message
The Following User Says Thank You to vinniekq2 For This Useful Post:
Vberg (08-22-2012)
  #6 (permalink)  
Old 08-22-2012, 04:17 PM
Registered User
 
Join Date: May 2012
Location: Central Iowa
Age: 19
Posts: 41
Wiki Edits: 0

Thanks: 6
Thanked 1 Time in 1 Post
So anything around 100 should be safe? I'll have to look into it some more

Thanks for the advice!
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 08-22-2012, 04:20 PM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 7,840
Wiki Edits: 0

Thanks: 313
Thanked 750 Times in 721 Posts
make sure your fuel delivery is good
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 08-22-2012, 05:10 PM
Registered User
 
Join Date: May 2012
Location: Central Iowa
Age: 19
Posts: 41
Wiki Edits: 0

Thanks: 6
Thanked 1 Time in 1 Post
Alright thanks for the help! I appreciate it!
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 08-23-2012, 09:49 AM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 36
Posts: 806
Wiki Edits: 0

Thanks: 91
Thanked 60 Times in 50 Posts
Personally I would avoid nitrous. Now you have to go to a gas station to get gas, and a hot rod shop to get the bottle filled. And when you are out of nitrous you still have a dog motor. I would rather have a good running engine 100% of the time. You could start with intake and exhaust as has already been suggested.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 08-23-2012, 11:13 AM
Registered User
 
Join Date: May 2012
Location: Central Iowa
Age: 19
Posts: 41
Wiki Edits: 0

Thanks: 6
Thanked 1 Time in 1 Post
We already put on new exhaust and headers but its still kind of a roach. I personally think he needs a new intake and carb next but I know someone with an extra nitrous kit laying around so I figured it would be cheaper to just put that on...I don't know though thats a very good point...what would you recommend as far as an intake?
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 08-23-2012, 11:29 AM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 36
Posts: 806
Wiki Edits: 0

Thanks: 91
Thanked 60 Times in 50 Posts
The intake in and of itself can add a few HP and torque numbers, but it is not going to make a huge difference. Is the motor factory, or have other mods been done to it? What kind of transmission? Assuming its an auto you should probably consider the Edlebrock performer RPM (1,500-6,500 RPM). The regular Performer intake is idle-5,000 RPM. Keep in mind the qjet is a spreadbore carb and most aftermarket Holley and Edlebrocks are going to be squarebore. So you either need an adapter (which is generally frowned upon), or get an intake to match the carb bolt and barrel config.

I am guessing you have a 750 CFM quadrajet carb. That is more than capable of handling your motor. I would spend money on rebuilding and tweaking it instead of putting on an aftermarket one. If you are not comfortable doing this, then send it out for a pro to work it. There is a qjet book by Cliff Ruggles that is considered the best book. The carb in and of itself is not going to make power. Larger CFM allows the engine to make more power, but larger barrels=less air velocity and that kills low end power. The qjet is a spreadbore carb so the primaries are small which HELPS low end power.

Not sure how much you are looking to spend or how much work you want to do/mechanical ability, but a good top end kit would wake the motor up (cam, heads, intake, and exhaust). I think most everyone would agree that the 1971 heads you have are relics and only good if you must have a numbers matching car. You can get some modern day factory GM Vortec heads and gain 25-50 HP. They are incredibly cheap too.
Reply With Quote Quick reply to this message
The Following User Says Thank You to Silver Surfer For This Useful Post:
Vberg (08-23-2012)
  #12 (permalink)  
Old 08-23-2012, 11:32 AM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 36
Posts: 806
Wiki Edits: 0

Thanks: 91
Thanked 60 Times in 50 Posts
The other possibility is that you are using modern day motor oil without a ZDDP additive and have wiped the cam lobes and lifters and that is why performance is suffering. No way to fix that without a new cam and lifters and start using a dedicated oil for flat tappet cams or an additive.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 08-23-2012, 01:07 PM
Registered User
 
Join Date: Nov 2004
Location: California
Age: 67
Posts: 828
Wiki Edits: 0

Thanks: 27
Thanked 21 Times in 19 Posts
Another option, for more APPARENT power, and better performance, is a gear ratio change. Is he on 3.08:1 gears now?

Pat
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 08-23-2012, 05:09 PM
Registered User
 
Join Date: May 2012
Location: Central Iowa
Age: 19
Posts: 41
Wiki Edits: 0

Thanks: 6
Thanked 1 Time in 1 Post
Silver Surfer,
I'm 99% sure the motor is completely factory...the tranny is a 350 (think it needs to be rebuilt cause it shifts soft but that could just be how they are)...I just put an Edlebrock Performer RPM on a 400 sbc I built for my car...I do believe you are right about the quadrajet and I've rebuilt a couple carbs before so as long as its a reasonably simple to do I'd be tempted but I've heard people say just to send them out to a pro but I'm not sure why...I'm probably going to talk to my friend about doing top end work because we all enjoy motor work the only problem is I don't know what he wants to spend but I didn't think about new heads but that sounds like a good idea to do a cam with new heads and intake...I know for sure you are right about the oil. Does it make that much of a difference?
Thanks for the input I greatly appreciate it!

PatM
I have no idea what he has for gears but I've been trying to get him to check that out. All I know is its a posi but I have no idea what the ratio is.


I also got a nitrous kit for next to nothing today but its for a fuel injected motor so does anybody know if there is an easy way to switch it for carbureted?
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 08-24-2012, 11:36 AM
my87Z's Avatar
Veteran/Firefighter-EMT-I CRT
 
Join Date: Mar 2009
Location: maryland
Age: 30
Posts: 1,685
Wiki Edits: 0

Thanks: 6
Thanked 11 Times in 11 Posts
As has been mentioned the first things are to get headers, free flowing exhuast, less restrictive intake. I agree with silversurfer that the Q-jet is just fine (great street motor carb). Once all of this has been done, the next (if not the very first) thing to be done should be to change out the gears to something shorter. Since this sounds like a factory car I wouldn't say that he needs more than a 3.73:1 rear gear, after that you could look into just putting a simple shift kit into the transmission.

I personally would stay away from nitrous (too many factors involed with using nitrous).

if after all this the guys still wants more power then he will need to do a head and cam swap (it's kinda pointless doing one without the other).

do a forum search on here about the easy way to check the gear ratio.
Reply With Quote Quick reply to this message
The Following User Says Thank You to my87Z For This Useful Post:
Vberg (08-24-2012)

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
Need 350 SBC to 350 Turbo Torque Specs MikeD Transmission - Rearend 2 10-20-2013 09:26 AM
SBC 350 / SBC 383: Verification Tips and Methods lt1silverhawk Hotrodding Basics 8 06-17-2011 12:21 PM
350 sbc with t-350 Trans, size of bolts to blockneeded? Canuckcamaro Transmission - Rearend 2 03-10-2011 06:46 PM
newer sbc 350 to older turbo 350 yragat Transmission - Rearend 8 10-20-2007 07:52 PM
0.060 over 350 sbc or 0.040 over 400 splayed cap sbc tony350ss Engine 4 05-17-2003 09:02 PM


All times are GMT -6. The time now is 02:29 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.