rebuliding a 350 to atleast 375 horse? - 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 05-18-2011, 08:12 AM
Registered User
 
Last photo:
Join Date: May 2011
Location: Iowa City Ia
Posts: 25
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
rebuliding a 350 to atleast 375 horse?

whats the easiest and cheapest way to rebuild a 350 to have atleast 375 horse and a decent amount of torque? as far as cam, carburetor, headers, distributor, possibly using stock crank and heads. want to put in a 86 caprice classic with the original 305. without boring the cylinders. open to any more suggestions. thanks in advance.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 05-18-2011, 08:15 AM
Registered User
 
Last photo:
Join Date: May 2011
Location: Iowa City Ia
Posts: 25
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
oh and replacing intake and looking for better air cleaner
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 05-18-2011, 01:00 PM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,038
Wiki Edits: 0

Thanks: 3
Thanked 362 Times in 358 Posts
Does your stock 350 short block have dished pistons?

What is the casting number on the cylinder heads?
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 05-18-2011, 03:57 PM
Registered User
 
Last photo:
Join Date: May 2011
Location: Iowa City Ia
Posts: 25
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
havent got the 350 yet, but im buying one from this guy and im gonna take it apart to see what i have.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 05-18-2011, 04:46 PM
adantessr's Avatar
'23 T-Bucket Pickup
 
Last wiki edit: Troubleshooting ignition Last photo:
Join Date: Jun 2010
Location: South Charleston , WV
Age: 62
Posts: 1,549
Wiki Edits: 3

Thanks: 43
Thanked 17 Times in 15 Posts
I'll be watching this.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 05-18-2011, 05:32 PM
LATECH's Avatar
Hotrodders.com Moderator
 

Last journal entry: Motor - vator
Last photo:
Join Date: Jul 2010
Location: Northeast Pennsylvania
Posts: 5,218
Wiki Edits: 0

Thanks: 203
Thanked 258 Times in 240 Posts
DOH ......
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 05-19-2011, 09:44 AM
adantessr's Avatar
'23 T-Bucket Pickup
 
Last wiki edit: Troubleshooting ignition Last photo:
Join Date: Jun 2010
Location: South Charleston , WV
Age: 62
Posts: 1,549
Wiki Edits: 3

Thanks: 43
Thanked 17 Times in 15 Posts
Quote:
Originally Posted by latech
DOH ......
Don't know what DOH means, but I sure want to see how to build a 375 hp 350 using strictly bolt ons, short of turbocharging or a blower. And of course retaining the stock heads. I'm sure there is a market for it. I know there were a lot of factory 350 hp 350s in 'vettes, but that was the old rating system. Please someone help this guy. I want to build one also. ( tongue in cheek )
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 05-19-2011, 11:55 AM
Sick467's Avatar
Registered User
 

Last journal entry: Wheels and Exhaust.
Last photo:
Join Date: Nov 2010
Location: Farmington, Mo
Posts: 48
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I'm not up on the latest Chevy stuff, but my rule of thumb is...

You can build 1 HP per Cubic Inch if...

1.) You get your Compression Ratio to 10:1 or better (91+ Octane, this means dome tops and possibly some block/head milling).
2.) Large Valve Iron High Performance Stock Heads or the Equivilent aftermarkets, actually the aftermarkets are typically bigger/better.
3.) Long Tube Headers.
4.) Portmatch Intake to Heads and Heads to Headers.
5.) Open up the Intake and Exhaust Runners.
6.) Electronic Ignition (Debatable).
7.) 4 barrel carb or equivelent.
7.) Street/Strip Cam.

That should get it to 350HP at the Flywheel. Now, Throw a good aluminum intake and some aluminum heads on it which allows for even higher compression ratio. You'll get the extra 25HP from the extra CR and aluminum heads, and chances are the aluminum heads will flow better than the highpo iron ones which should kick you right up there.

Stoke it to 383 and whooohhoo!!, but that's getting away from "the cheapest".

Well, Obviously this rule of thumb leaves some holes, but I hope you get the main idea. Remember, money builds HP, if you go cheap cheap then you'll fall short of 350.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 05-19-2011, 12:16 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by runway1589
havent got the 350 yet, but im buying one from this guy and im gonna take it apart to see what i have.
Until you can answer the question of what heads and pistons you have, there's no point in telling you a recipe for making "X" HP, just not enough to go on.

That said, most factory 350 SBC engines came w/dished pistons of around 10-12cc volume. With a 64 cc head, the CR is roughly 9.15 to 9.7 depending on the gasket thickness and the deck height. With the 76 cc heads like you most likely will have, the CR will be 8.2 to 8.6:1.

An un-rebuilt 350 SBC engine is getting harder to find any more. Most have been rebuilt at least once, it seems. When you get the heads off, look to see how much wear ridge shows at the tops of the cylinders and if there's an oversize stamped into the tops of the pistons. If there's nothing stamped, this doesn't mean their not oversize, but many replacement pistons are marked that way.

Because you're not planning on boring it you're at the mercy of whatever wear and tear is on the engine. If I were doing this deal, the very least I'd do would be to rering it unless the history is known and indicates the engine wasn't tired. You'll need to pull the caps off the bottom end to see what you have there, too.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 05-19-2011, 12:36 PM
LATECH's Avatar
Hotrodders.com Moderator
 

Last journal entry: Motor - vator
Last photo:
Join Date: Jul 2010
Location: Northeast Pennsylvania
Posts: 5,218
Wiki Edits: 0

Thanks: 203
Thanked 258 Times in 240 Posts
DOH ( see homer simpson)
Just curious how it will run ( providing it is built ) in an 86 caprice. It will need a stall converter (say 2500 rpm) and a gear , dontcha think? Oh and a shell card for fuel wouldnt be a bad Idea.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 05-19-2011, 01:12 PM
adantessr's Avatar
'23 T-Bucket Pickup
 
Last wiki edit: Troubleshooting ignition Last photo:
Join Date: Jun 2010
Location: South Charleston , WV
Age: 62
Posts: 1,549
Wiki Edits: 3

Thanks: 43
Thanked 17 Times in 15 Posts
Quote:
Originally Posted by Sick467
I'm not up on the latest Chevy stuff, but my rule of thumb is...

You can build 1 HP per Cubic Inch if...

1.) You get your Compression Ratio to 10:1 or better (91+ Octane, this means dome tops and possibly some block/head milling).
2.) Large Valve Iron High Performance Stock Heads or the Equivilent aftermarkets, actually the aftermarkets are typically bigger/better.
3.) Long Tube Headers.
4.) Portmatch Intake to Heads and Heads to Headers.
5.) Open up the Intake and Exhaust Runners.
6.) Electronic Ignition (Debatable).
7.) 4 barrel carb or equivelent.
7.) Street/Strip Cam.

That should get it to 350HP at the Flywheel. Now, Throw a good aluminum intake and some aluminum heads on it which allows for even higher compression ratio. You'll get the extra 25HP from the extra CR and aluminum heads, and chances are the aluminum heads will flow better than the highpo iron ones which should kick you right up there.

Stoke it to 383 and whooohhoo!!, but that's getting away from "the cheapest".

Well, Obviously this rule of thumb leaves some holes, but I hope you get the main idea. Remember, money builds HP, if you go cheap cheap then you'll fall short of 350.
Just curious as to what RPM you have to turn to get 375 hp. My T-Bucket upshifts @ 4000 . Allan
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 05-19-2011, 01:35 PM
malc's Avatar
Living At The Speed Of Life
 
Last photo:
Join Date: Jun 2003
Location: Espaņa Right Coast
Posts: 3,259
Wiki Edits: 0

Thanks: 90
Thanked 93 Times in 79 Posts
According to my Desktop Dyno I get just over 350HP, but not for long.
I have a Crane Powermax cam I bought for my old 305 computer controlled engine, gives good torque, Brodix heads, Edelbrock Airgap, Hedmann Hedders,
all MSD ignition and a 750 Speed Demon.I have just installed thinner head gaskets to up the compression, 10.12:1, luckily here in Spain we have 95 and 98 octane pump gas.
As you can see the motor pulls hard from 2000 to 4500rpm when the cam runs out of puff, used only on the street the car rarely sees over 3000.
Go for torque over HP, itīs what moves the car.

Big view.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 05-19-2011, 01:54 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by malc
...luckily here in Spain we have 95 and 98 octane pump gas.
Correct me if I'm wrong, but isn't your octane figured by using the RON (Research Octane Number)? Here in the states we use the AKI (Anti Knock Index), which is an average of the RON and MON (Motor Octane Number) to arrive at an octane rating. The RON is about 5 points lower than our rating system, so "your" 95 octane is about like "our" 90 octane, etc. Still decent fuel, but possibly just not as good as the numbers would first lead you to believe.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 05-19-2011, 02:00 PM
malc's Avatar
Living At The Speed Of Life
 
Last photo:
Join Date: Jun 2003
Location: Espaņa Right Coast
Posts: 3,259
Wiki Edits: 0

Thanks: 90
Thanked 93 Times in 79 Posts
If I can remember Iīll check at the pump next time.
At least I can use the 95, no knocking.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 05-21-2011, 07:20 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,021
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
do yourself a favor and start with a factory roller block.


here is a 400hp build for 1000.00

http://www.superchevy.com/technical/...ild/index.html
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
I have a 350 crate engine i want to make atleast 400 hp. chevydragster83 Engine 36 08-26-2012 12:47 PM
408 build... trying atleast soon2be Engine 29 11-30-2009 11:19 AM
how much horse? mitch69 Engine 7 12-13-2005 07:02 AM
450 horse 350 drevvski63 Engine 1 03-30-2003 10:42 PM
300 horse 283 drevvski63 Engine 8 03-28-2003 06:18 PM


All times are GMT -6. The time now is 01:36 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.