What is the best way to build up a chevy 305? - 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 12-18-2003, 12:40 PM
sugarmonkey's Avatar
Registered User
 
Join Date: Dec 2003
Location: Concord
Age: 27
Posts: 5
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
What is the best way to build up a chevy 305?

Hello everybody my name is Jim. I have recently purchased a 1986 chevy camaro iroc z-28. It has a chevy HO 305 TPI with about 125,000 miles on it. I am prepared to rebuild it but im not sure what to do with it. People are telling me to bore it up, slap some vortec heads on it, put a mild cam in it. Im new to domestic performance. My goal is to bring it down to the mid 12 sec range for a 1/4 mile. The current time for it is 14.5. It is completely stock except for the transmission which has a few performance shift parts (its auto). If anyone has any suggestions please respond to this, but please dont just say go and get a 350 because i want to keep this as close to stock appearance as possible. Thank You.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-18-2003, 01:04 PM
johnsongrass1's Avatar
Race it, Don't rice it!
 
Last photo:
Join Date: Jul 2002
Location: Columbia, Mo
Age: 38
Posts: 4,080
Wiki Edits: 0

Thanks: 0
Thanked 10 Times in 10 Posts
How much do you want to spend? It cold be costly to get those numbers. You'll need around 380 horse and good traction.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-18-2003, 02:18 PM
stepside454's Avatar
Member
 
Last photo:
Join Date: Dec 2003
Location: St. louis area
Age: 47
Posts: 1,074
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
First off, a 350 & a 305 virtually look the same.
Boring an engine is basically to recondition the cylinders, it probably needs it anyway, but boring an engine out isnt a big performance gain if the cylinders are good to start with.
I dont think Vortec heads will work with your TPI intake. A better choice maybe World Products S/R305 heads. I used KB 143 pistons in my 305 with the same size cumbustion chamber.. it comes out to a pump gas friendly 10:1 compression. I know there are aftermarket runners & thorattle bodys for the TPI although Ive never used em.
86... Im not sure if the 86 TPIs were roller or flat tappet...my 305 is an 86 flat tappet...but it was carbed. A roller would be a much better choice.
of course a set of headers... even if there shorty headers would help, as well as a good ignition system.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-18-2003, 03:15 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
best way to build up a 305? easy, Install a 350.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-18-2003, 03:45 PM
Thom Laybourne's Avatar
Member
 
Last photo:
Join Date: Sep 2003
Location: CA
Age: 72
Posts: 448
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
350

Yup, most pros couldn't tell if it was a 305 or 350 from the outside. Put some heads on and it changes the appearance. We are not being mean. Junk yards sell short blocks for about 75 tops. Bore the 305-3.85 to 4.0 change the crank and you have a 350. Lots of neat things to do and everyone has their own color of paint to paint the picture. Stay true to your idea. The heads are good start, roller if you can, headers are always helpers. And I can not say enough for a good Dyno-Shop. They usually run about 400 for a good run. Wish I had started when I was 17.

hr41pearl
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 12-18-2003, 04:13 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
Thom, you post has me confused, I never heard of anyone boring a 305`s 3.736 bore to 4.000 inches. the stroke is the same of the 305/350, so if you could bore a 305 that far you`d have a 350.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 12-18-2003, 04:33 PM
Thom Laybourne's Avatar
Member
 
Last photo:
Join Date: Sep 2003
Location: CA
Age: 72
Posts: 448
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Point Made

305 Looks just like a 350. Bore it and it is a 350. You can not see the bore when the engine is installed. 383 Looks just like the both of them. Change crank. The lad sounds like he wants to save money or at least point it toward specifics. We know that a 383 will get him to the time he wants faster than anything else. He will see it eventually.

hr41pearl
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 12-18-2003, 05:07 PM
NorthStar's Avatar
Member
 
Last photo:
Join Date: Feb 2003
Location: Minnesota
Age: 51
Posts: 847
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
You cant bore out that much the cylinders would be paper thin.


All the same tricks that work on a 350 will work on a 305 start hunting down a good set of heads.
If it was me Id use flattop pistons shoot for 9.5 to 1 compression, about a 270 duration cam, headers, and spend all the extra money you got on cylinder heads biggest valves you can squeeze in there and port them.

Last edited by Greg Latvala; 12-18-2003 at 05:14 PM.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 12-18-2003, 09:26 PM
Registered User
 
Join Date: Dec 2001
Location: torrance ,calif
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
305 heads

hey you have to be carful putting big valve heads on a 305 , the bores arent big enough for big valves , you might want to check it out befor you spend a bunch of money on heads
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 12-18-2003, 09:31 PM
badknuckles's Avatar
you talkin to me?
 
Join Date: Nov 2003
Location: fort lewis, wa
Age: 33
Posts: 1,094
Wiki Edits: 0

Thanks: 3
Thanked 0 Times in 0 Posts
i knew someone with a 86 iroc 305 ran 12.4 stock with ported and polished heads whipple charger different intake throttle body runners intake ignition but stock lower end lot of money but hey its a 305 get a 350 it would be cheaper.
keep those heads there h.o. heads so they flow nice and have bigger valves
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 12-18-2003, 09:31 PM
lluciano77's Avatar
Short changed on common sense
 
Last photo:
Join Date: Jun 2003
Location: california
Age: 37
Posts: 3,548
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally posted by DoubleVision
best way to build up a 305? easy, Install a 350.

Here is the best advice.

Why spend the money to make a 305 faster when you could have a late model roller cammed 350? If they both had the same power, the 305 would run like a popcorn machine and the 350 would run smoothly.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 12-19-2003, 12:18 AM
New Member
 
Join Date: Apr 2003
Posts: 10
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The last two threads said it all. I was looking into rebuilding a 305 for my truck and found that it was more expensive to rebuild the 305 then to purchase a used 350 and rebuild it. Krunch some numbers and see where the money falls!
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 04-20-2004, 09:46 AM
Registered User
 
Join Date: Apr 2004
Location: Michigan
Posts: 2
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
We must be in the same boat.

I have been working on that same question. I have two cars with 305s. One is my daughter's, the 86 Z28, and mine is a 77 caprice. The camaro runs great so Im not touching it. The caprice I'v been working on. I started by porting the stock Q-jet intake to match the gaskets (including the carb gasket). I smoothed out any sharp corners I could reach with a file and a grinding stone. I'ts cheeper but not as easy as buying an edelbrock performer. I instaled a summit cam, roller timing chain, and some 305 HO heads with 184 intake valves (these heads should be on your camaro). Before instaling the heads I gasket matched the intake ports and smoothed out the exhaust ports. I also ported my exhaust manifolds. Headers would be easier and flow better. I would have gone with a roller cam but I dont know how much lift the stock valve springs will handle. Some better flowing heads would be W.P. S/R Torker 305 heads with 194 intake valves and 58cc chambers. I heard of a 305 camaro turning 9s with turbos. Good luck. Hayden
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 04-20-2004, 09:54 AM
Grumpy
 
Last photo:
Join Date: Dec 2002
Location: D.C.
Posts: 1,447
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Re: 350

Quote:
Originally posted by Thom Laybourne
Yup, most pros couldn't tell if it was a 305 or 350 from the outside. Put some heads on and it changes the appearance. We are not being mean. Junk yards sell short blocks for about 75 tops. Bore the 305-3.85 to 4.0 change the crank and you have a 350. Lots of neat things to do and everyone has their own color of paint to paint the picture. Stay true to your idea. The heads are good start, roller if you can, headers are always helpers. And I can not say enough for a good Dyno-Shop. They usually run about 400 for a good run. Wish I had started when I was 17.

hr41pearl
Your thinking of an olds 307, their bore is 3.80
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 04-20-2004, 10:45 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
Bore a 305 to a 4.000 inch bore and there wouldn't even be bores anymore, you'd be looking at a water jacket.

K
Reply With Quote Quick reply to this message
The Following User Says Thank You to killerformula For This Useful Post:
grandslam1991 (03-18-2014)

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



All times are GMT -6. The time now is 10:42 PM.


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.