Hot Rod Forum : Hotrodders Bulletin Board - Reply to Topic -- 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> Anyone know the stock compression ratio for a 1979 350 chevy ?
User Name
lost password?   |   register now

Thread: Anyone know the stock compression ratio for a 1979 350 chevy ? Reply to Thread
Send Trackbacks to (Separate multiple URLs with spaces) :

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.

Additional Options
Miscellaneous Options

Topic Review (Newest First)
06-11-2012 09:31 PM
79bird My Firebird with a 305 is at 8.5 right now stock, yours should be in the same relm
06-11-2012 02:29 PM
78novaman According to my Hayne's manual:

8.2:1 for light duty trucks
8.3:1 for heavy duty trucks

All I can think is maybe slightly different pistons???
06-05-2012 06:09 PM
GMCBEAST I agree with above, 8-8.5:1. Those 76cc heads (Most likely what you have) kill compression, throw in a dished piston and you end up on the low end of the C.R. ladder. On the good side you don't need premium gas. If they are dished pistons I think they are 18cc cups, I'm not positive though, 58cc chambers are ok with dished or most 4 valve relief flat tops but you need to pay close attention to your timing with the flat tops. Summit and Wallace Racing have a compression ratio calculator on their site's once you figure out your specs. Hope this helps.
06-05-2012 05:23 PM
75gmck25 If its stock, then not more than 8.5.

If you measure it you may find some engines calculate out as low as 8.1.

06-05-2012 10:40 AM
Madmax305 I don't know exactly, but you can figure in the 8.5-9.0 compression ratio.
06-05-2012 10:35 AM
Anyone know the stock compression ratio for a 1979 350 chevy ?

it came out of a truck and as far as i've researched it had 175 hp and 250tq back in the day, previous owner said it is completely stock, does anyone know the compression ratio that came in this engine ? or perhaps the cc's of the pistons

I'm trying to get an accurate compression estimate because i just bought a set of 305 cylinder heads 601 casting which have been ported and machined to have 58cc chambers and 2.02 intake and 1.60 exhaust valves

the engine has a slightly more aggressive than stock cam and i'm hoping for a tad bit under 9:5:1 compression so i can run 89 octane

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

All times are GMT -6. The time now is 02:50 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.