Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Sponsored by:
Sponsored by: CARiD

Compression of 79 Chevy Truck 350?

Thread Tools
 
Search this Thread
 
Old Jan 27, 2001 | 07:18 PM
  #1  
Mike86Z28's Avatar
Thread Starter
Member
 
Joined: Jul 1999
Posts: 137
Likes: 0
From: Midwest City, Ok, USA
Car: 98 Z28
Engine: LS1
Transmission: T56
Axle/Gears: 3.42
Compression of 79 Chevy Truck 350?

What is the compression ratio of a 79 Chevy truck 350? Any websites ya'll can direct me to so I can find out more info?
Reply
Old Jan 27, 2001 | 07:28 PM
  #2  
RB83L69's Avatar
Supreme Member
 
Joined: Jul 1999
Posts: 18,457
Likes: 16
From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
~8.5:1

You found this website... What info would you like?

------------------
"So many Mustangs, so little time..."
ICON Motorsports
Reply
Old Jan 28, 2001 | 02:01 PM
  #3  
bhaas's Avatar
Senior Member
 
Joined: Oct 2000
Posts: 822
Likes: 0
From: Tac. Wa. USA
I have a 1979 350 truck motor in my Camaro.
8.5:1 seems kinda low. It doesn't have the original heads. Would that make any difference? What kind of compression should I expect on a compression tester?

Thanks.
Reply
Old Jan 28, 2001 | 02:39 PM
  #4  
RB83L69's Avatar
Supreme Member
 
Joined: Jul 1999
Posts: 18,457
Likes: 16
From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
Since heads are one of the 2 things that have the biggest impact on the static compression ratio, then if yours aren't the original, your CR might be different. Whether it seems low or not, 8½:1 is what those motors had; that's a big part of why they're such pigs in their original trim.

That motor came with dished pistons and 76cc heads, just like millions of other 350s from the mid and late 70s. It was a terrible motor in its factory form, rated at 185 HP IIRC. It's a very familiar motor. I have had several cars that had it, and so have my friends & family; it came in everything from Novas to Impalas to Monte Carlos to trucks to Z28s. It was sort of the universal Chevrolet motor for a number of years.

Compression tester reading vary widely, being affected by a huge number of factors, from cam profile to engine temp. Typical numbers for that motor as it came from the factory were in the 170 psi neighborhood, with the engine completely cool. Yours could be considerably different from that, depending on the particular heads that you have.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited January 28, 2001).]
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
jhawkeye
Engine Swap
5
May 25, 2022 06:33 PM
Reborn756
Tech / General Engine
142
Sep 4, 2015 03:42 AM
Eric-86sc
Engine/Drivetrain/Suspension Parts for Sale
0
Aug 24, 2015 09:01 PM
NinjaNife
Tech / General Engine
27
Aug 23, 2015 11:49 AM
theshackle
Tech / General Engine
2
Aug 22, 2015 06:52 PM




All times are GMT -5. The time now is 05:31 PM.