Search



Go Back   Third Generation F-Body Message Boards > Tech Boards > Tech / General Engine
Sign in using an external account
Register Forgot Password?

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 Weld Racing
Click Here

Welcome to ThirdGen.org!
Welcome to ThirdGen.org.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!


Reply
 
Thread Tools Search this Thread
Old 06-08-2010, 07:47 PM   #1
Junior Member
 
Join Date: Sep 2009
Posts: 15

Classifieds Rating: (0)
350 or 305? How to identify?

I'm going to look at an 88 GTA trans am tomorrow and the guy says a mechanic told him it has a 350 in it now.

I checked the vin# and it was an LB9 and it's a T5 also.

he says you can't see the casting #'s on the block behind the drivers side head so is there a quick way to tell by looking at something else on the engine?

the old 305's had a hollowed out harmonic balancer on the back side....do the newer ones?
dirtywhiteboy is offline vBGarage Page   Reply With Quote
Old 06-08-2010, 07:53 PM   #2
Moderator
 
AlkyIROC's Avatar
 
Join Date: Jul 1999
Location: 51°N 114°W, 3500'
Posts: 15,307
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86

Classifieds Rating: (0)

Re: 350 or 305? How to identify?

Casting numbers are the easiest way. You can't use a 305 casting to make a 350. Some blocks have 5.0L or 5.7L cast into the block either at the back near the casting number or on the side.

On the pad in front of the passenger side head are a bunch of numbers and letters stamped into the pad. These can usually tell you what the engine is and what it originally came out of. If the block has ever been decked, these numbers get machined off.

The last way is to pull a head and measure the bore.

External components on the engine can't tell you the engine displacement.

Unless someone has changed something, you probably have a 305. A T5 didn't come behind a 350. If it's really a LB9/T5 1988 GTA, and has the G92 RPO code it will have a 9 bolt diff with 3.45 gears. You can easily check to see if it's a 9 bolt or not.
__________________
Hardtail Racing
All engine, no power adders! Bests: 9.029@150.45 (at altitude)
Theoretical sea level performance 8.623@157.05

Last edited by AlkyIROC; 06-08-2010 at 07:57 PM.
AlkyIROC is offline vBGarage Page   Reply With Quote
Old 06-08-2010, 07:54 PM   #3
Junior Member
 
Join Date: Feb 2010
Posts: 81

Classifieds Rating: (0)
Re: 350 or 305? How to identify?

i picked up a 350 not to long ago that had a 305 balancer and it was completely stock, you are going to have to pull a head, if it wasnt swapped before than its a 305 because 350s didnt come with t5s if i remember right
shanep1991 is offline vBGarage Page   Reply With Quote
Old 06-09-2010, 08:51 PM   #4
Supreme Member
 
'87IROCZOWNER69's Avatar
 
Join Date: Mar 2010
Location: Omaha, NE
Posts: 1,078
Car: 1987 IROC-Z, 98 GTP, 00 Intrepid
Engine: 5.7 350 V8, 3.8 SC, and 3.5 HO swap
Transmission: 700R4 Automatic Transmission
Axle/Gears: 3.27 Posi

Classifieds Rating: (1)
Re: 350 or 305? How to identify?

I agree that measuring the bore would be easiest because if its 3 inches than it is a 350 but if it is 2.5 then it is a 305. Even if you cant figure it out from that one of the easiests things to do is to take it to your local dyno. The LB9 would do 220 horse and the L98 would do 230 horse. But from what I have heard and read is that none of the 350s came with manuals they all came with the 700R4. The reason is because the manuals could not handle the power that the 350s were putting out.
'87IROCZOWNER69 is offline vBGarage Page   Reply With Quote
Old 06-10-2010, 01:11 AM   #5
Supreme Member
 
Join Date: Apr 2005
Location: Not in Kansas anymore
Posts: 7,490
Car: 90 Vette / 67 Camaro / 87 Vette
Engine: 383 SP EFI /383 LT1 /L98 TPI
Transmission: T400 /200R4 /T700
Axle/Gears: 9" 3.90 /12 Bolt 4.11 /D44 3.07

Classifieds Rating: (13)
Re: 350 or 305? How to identify?

Quote:
Originally Posted by '87IROCZOWNER69 View Post
I agree that measuring the bore would be easiest because if its 3 inches than it is a 350 but if it is 2.5 then it is a 305.
Back to skool
350 has 4.00" bore
305 has 3.7" bore
vetteoz is offline vBGarage Page   Reply With Quote
Old 06-21-2010, 11:20 AM   #6
Member
 
kd5icr's Avatar
 
Join Date: Jan 2010
Location: Carrollton Texas.
Posts: 446
Car: 1985 Camaro Z28
Engine: 305 mild build up
Transmission: 700r4
Axle/Gears: Stock

Classifieds Rating: (2)
Re: 350 or 305? How to identify?

You can get an large inspection mirror and and use it to see the casting numbers on the back of the engine. On some late model engines the last 3 digits of the casting number is also on the side of the engine between the freeze plugs (either side) And these are large enough to read.
And as a shot in the dark you could pull a valve cover off and check the casting number off of the head, now unless they put 305 heads on a 350 (or the other way around but I doubt that) you can figure that it is either a 305 or a 350.
__________________
Motivational speaker Zig Ziglar states, “Money isn't the most important thing in life, but it's reasonably close to oxygen on the ‘gotta have it’ list;”

85 Z28.
305 carb,mild street cam
700r4 with stock rear end
Shorty headers.

Last edited by kd5icr; 06-21-2010 at 11:24 AM.
kd5icr is offline vBGarage Page   Reply With Quote
Old 06-21-2010, 11:47 AM   #7
Supreme Member
 
Join Date: Sep 2002
Location: Texas
Posts: 2,552
Car: 1992 Formula Firebird
Engine: 305CID (LB9)
Transmission: World Class T5
Axle/Gears: 10-bolt, 4.10 gears

Classifieds Rating: (1)

Send a message via MSN to 87WS6
Re: 350 or 305? How to identify?

The last three digits of the casting numbers on the sides of the block should be present on at least the 1985-1992 third generation F-body engines. If the engine does not have the casting numbers on the sides, then most likely the engine isn't original. That doesn't tell you if it is a 305 or a 350 if the casting number isn't easily readable, but if the casting number isn't present then it very well could be a 350 engine. If the casting number is present you can verify what it is quite easily.

Most 305 engines in the F-Bodies I've seen have a 627 casting on the sides of the block. At least the TPI engines do.
87WS6 is offline vBGarage Page   Reply With Quote
Old 06-21-2010, 12:13 PM   #8
Member
 
kd5icr's Avatar
 
Join Date: Jan 2010
Location: Carrollton Texas.
Posts: 446
Car: 1985 Camaro Z28
Engine: 305 mild build up
Transmission: 700r4
Axle/Gears: Stock

Classifieds Rating: (2)
Re: 350 or 305? How to identify?

Quote:
Originally Posted by 87WS6 View Post
The last three digits of the casting numbers on the sides of the block should be present on at least the 1985-1992 third generation F-body engines. If the engine does not have the casting numbers on the sides, then most likely the engine isn't original. That doesn't tell you if it is a 305 or a 350 if the casting number isn't easily readable, but if the casting number isn't present then it very well could be a 350 engine. If the casting number is present you can verify what it is quite easily.

Most 305 engines in the F-Bodies I've seen have a 627 casting on the sides of the block. At least the TPI engines do.
You sir are dead on, thats why I also said that he can pull off a valve cover and use the casting numbers from the head. Most factory engines will use a 350 head with a 350 and a 305 head for a 305, this is a rule of thumb thing.
kd5icr is offline vBGarage Page   Reply With Quote
Old 06-21-2010, 12:13 PM
ThirdGen
1992 Camaro




Paid Advertisement


Reply

Go Back   Third Generation F-Body Message Boards > Tech Boards > Tech / General Engine

Tags
1985, 305, 350, 350thirdgen, 627, block, casting, difference, engine, howto, identifing, identify, identifying, motor, tpi
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not 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 Off
Pingbacks are Off
Refbacks are Off

 


1982 Camaro '82 || 1983 Camaro '83 || 1984 Camaro '84 || 1985 Camaro '85 || 1986 Camaro '86 || 1987 Camaro '87 || 1988 Camaro '88 || 1989 Camaro '89 || 1990 Camaro '90 || 1991 Camaro '91 || 1992 Camaro '92


All times are GMT -5. The time now is 04:59 AM.


Powered by vBulletin® Version 3.7.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.5.2
All content copyright © 1997 - 2014 ThirdGen.org. All rights reserved. No part of this website may be reproduced without the expressed, documented, and written consent of ThirdGen.org's Administrators.

Emails & Contact Details