Is it a 305 or a 350? - Page 3 - Third Generation F-Body Message Boards

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Is it a 305 or a 350?

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Old 07-15-2010, 12:06 PM
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Re: Is it a 305 or a 350?

Just get up in the motor bay look behind the driver side head and it will have a long number or 5.0 or 5.7

for example the long number will be like 397000(this is a old 350 block)

If you have a number and cant figure it out let me know I can get it for you

we have all the old gm code books
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Old 07-17-2010, 06:17 AM
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Re: Is it a 305 or a 350?

There's really no way we're STILL talking about this? It's seven f***ing years old now!

But I've got a question actually, regarding the size of the engine from the outside on my '88 Formula.

What if there's no paint on the block and it's gray, and the casting #s are in different spots, and the balancer is the pulley too, and it has a large "5.3L" cast on the front of #1 cylinder?

I think it means 305's suck hippo a**.

Stock.

Last edited by dan_needs_a_ws6; 07-17-2010 at 06:20 AM. Reason: They won't let me say the three letter variable to donkey.
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Old 04-26-2011, 04:12 PM
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Re: Is it a 305 or a 350?

Well this is old but i really need to know. Is there anyway to see the casting number on the back of the engine without removing the engine??
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Old 04-26-2011, 04:21 PM
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Re: Is it a 305 or a 350?

sometimes you can. if you can't and need to know what the engine is, on the front passenger side of the engine right in front of the head is the suffix numbers and they can tell you what vehicle it was originally in. thats if the block wasn't decked
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Old 04-26-2011, 04:32 PM
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Re: Is it a 305 or a 350?

So those numbers will be on the block not the headers right? and closer to the back of the engine or the front?
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Old 04-26-2011, 04:36 PM
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Re: Is it a 305 or a 350?

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Old 04-26-2011, 04:43 PM
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Re: Is it a 305 or a 350?

i think i found it but it was more on the drivers side..didnt see anything on passengers. all i could make out was 2269 but theres more there but hard to see. Does that sound right?
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Old 04-26-2011, 05:08 PM
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Re: Is it a 305 or a 350?

no
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Old 04-26-2011, 05:20 PM
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Re: Is it a 305 or a 350?

im not seeing it..oh well i will find it eventually
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Old 12-02-2011, 11:33 PM
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Re: Is it a 305 or a 350?

VERY EASY. when you start the car, a 305 will crank over 4 times but a 350 will crank over 3.5 times before firing, duh. i also heard something about casting numbers, but since no one has mentioned it, cant be right, lol.
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Old 01-09-2012, 09:31 PM
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Re: Is it a 305 or a 350?

what year motor had an electric q-jet 4 barrel carb? or what year car did this start?
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Old 01-10-2012, 07:44 AM
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Re: Is it a 305 or a 350?

?
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Old 01-10-2012, 07:45 AM
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Re: Is it a 305 or a 350?

On a 305 the muffler bearings are on the drivers side and they don't have a grease nipple.
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Old 01-11-2012, 10:01 AM
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Re: Is it a 305 or a 350?

It's typically in the back, on the driver side?
Anyhow, this is the best list for casting numbers I've ever come across (including the one on this board)

http://outintheshop.com/faq/casting/castings2.html
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Old 04-14-2015, 01:24 AM
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Re: Is it a 305 or a 350?

Originally Posted by Air_Adam View Post
The '86 was not only not available with a 350/5-speed combo... it wasn't available with a 350!

The 350 wasn't an option untill 1987.

That does look like an unoriginal motor though, judging by the color (orange). The orange paint was used from 1955-77, after that was blue, then black in 1983.

It also has the drivers side dipstick too, which says that its a pre-1980 block.

Actually sorry to say that you are not only wrong, but you are very wrong. In 1986 Pontiac really put 350's in the ordinary Firebird but they discontinued putting the 350's in them because they had serious problems. Everyone thought the carburetor had serious problems feeding the engine the fuel to stay running.

When anyone, workers, owners of Pontiac plants, civilians, even the best mechanics then didn't realize that the carb was fine. They would look down in the butterfly the piece in the carb that turns straight up and down where you spray starting fluid. Well when they looked in it they wouldn't see any gas shooting through the carb fuel feeder jets at all no thick squirts or streams. Not even a little bit. They blamed the carb for no reason.

Why? Because everyone thinks that if you hear the fuel pump making noise then its working and pushing gas to the carb through the vacuum lines. That's not always true. Not even Pontiac realized that the pumps they were producing were junk that they quit after a couple hundred miles. They just kept making them slowly they made almost 100 of them. This is what i found with my sons research. They made almost 100 with 350s but within two months the fuel pumps went out and people junked them because they didn't know what the problem was and couldn't fix it. Well just so happens mine didn't get junked(luckily). Pontiac discontinued them because all they were doing was loosing so much money they over stocked all the fuel pumps, carb pieces, vacuum hoses, all pieces for the 350 firebird when they only made it for a couple months. So they used what little of the stock that worked and they put it on later made trans ams.


I only made this account so i could let my son comment on a couple of these. He has researched almost every motor that was even in any Pontiac gm factory. For the last three years that's all he has done when he isn't working on his 86 bird that has original stock 350 in it from the factory. I am a 16 year old boy from Ohio and knows more about Pontiac made cars then almost any mechanic. I can fix almost anything on a bird that's fixable. I am literally the worlds biggest firebird and trans am fan. I would never want another car besides my 86 firebird it sat in my dads yard since 1986, 6 months after he got it when my father took it to the shop because it wouldn't start and it was a Pontiac only shop and they said carburetor was completely toasted they would have to overhaul it. So they did still it would only run as long as you kept pouring gas or starting fluid in the butterfly and then almost as soon as you quit pouring or spraying it would shut off. So he parked it in his side yard and never even opened a door or window or touched it. Then my parents had me. When I was born he made plans that he told my mom that it was going to be a father son project when i turned 16. That was 16 years ago January 6th.

So about 5 weeks ago while it was covered in vines, sticks, berry's, about a 5 inch deep puddle underneath it, flat tires, and cracked windshield he hooked a tow chain to it and pulled it into a extra piece of the driveway. He raised the hood, charged a battery over night, got a gallon of gas and we were ready to see if it would start. My dad poured gas in the carb, me being hyper i expected the worse and hoped for the best. Well he said try it j and amazingly it started the first time the key was turned. That's 29 years later after just sitting . Remember we live in the south part of Ohio so every year we have bad storms, a lot of snow, a lot of rain, and falling tree branches. Normal people would say don't waist time or money on the car. Me and my dad loving the car so much we did anyway. So it shut off after the gas he poured in the carb ran out. So he didn't hear the fuel pump working so he took it off tried to fix it and i told him don't worry about it. So i wake up the next morning to a new fuel pump. It took about 1 to 2 hours to put it in. Finally he poured some sea foam, some dry gas, some stabilizer, and fresh gas in the tank because it had half tank of old gas in it. So he finally said try it. So i did, it started up and now runs fine. We looked up my vin number it says original 1986 Pontiac firebird 5.7l v8 350. Also i checked last 7 vin digits that you match with the engine plant code then last half off vin number to see if the motors the original match to the car. The owner guide says 1986 5.7l v8 350 firebird right on the owners manual.

Also i was talking to a Pontiac representative at gm motors today and after about 2 an 1/2 hours of him beating around the bush he said there was an 86 firebird with a 350 in it that Pontiac made for less than 5 months if that. Also that was company information only that they haven't told anyone that the public knows of. So please do not comment hate on this i have worked on this for about 3 years doing nothing but researching the 86 firebird 350 myth well you all know that it really wasn't a myth. Thank you for reading. Please research it better than most people do it could take as long as it took me to get all this info but you'll never know if you don't try. Please do not leave hate comments on this please. This is like my whole lifes work so far being 16. Thank you for reading this blog.
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Old 04-14-2015, 01:53 AM
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Re: Is it a 305 or a 350?

250
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Old 04-14-2015, 01:54 AM
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Re: Is it a 305 or a 350?

im sorry 350 it autocorrected to 250
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Old 04-17-2015, 02:10 PM
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Re: Is it a 305 or a 350?

Originally Posted by firebird final View Post
Actually sorry to say that you are not only wrong, but you are very wrong. In 1986 Pontiac really put 350's in the ordinary Firebird but they discontinued putting the 350's in them because they had serious problems. Everyone thought the carburetor had serious problems feeding the engine the fuel to stay running.

When anyone, workers, owners of Pontiac plants, civilians, even the best mechanics then didn't realize that the carb was fine. They would look down in the butterfly the piece in the carb that turns straight up and down where you spray starting fluid. Well when they looked in it they wouldn't see any gas shooting through the carb fuel feeder jets at all no thick squirts or streams. Not even a little bit. They blamed the carb for no reason.

Why? Because everyone thinks that if you hear the fuel pump making noise then its working and pushing gas to the carb through the vacuum lines. That's not always true. Not even Pontiac realized that the pumps they were producing were junk that they quit after a couple hundred miles. They just kept making them slowly they made almost 100 of them. This is what i found with my sons research. They made almost 100 with 350s but within two months the fuel pumps went out and people junked them because they didn't know what the problem was and couldn't fix it. Well just so happens mine didn't get junked(luckily). Pontiac discontinued them because all they were doing was loosing so much money they over stocked all the fuel pumps, carb pieces, vacuum hoses, all pieces for the 350 firebird when they only made it for a couple months. So they used what little of the stock that worked and they put it on later made trans ams.


I only made this account so i could let my son comment on a couple of these. He has researched almost every motor that was even in any Pontiac gm factory. For the last three years that's all he has done when he isn't working on his 86 bird that has original stock 350 in it from the factory. I am a 16 year old boy from Ohio and knows more about Pontiac made cars then almost any mechanic. I can fix almost anything on a bird that's fixable. I am literally the worlds biggest firebird and trans am fan. I would never want another car besides my 86 firebird it sat in my dads yard since 1986, 6 months after he got it when my father took it to the shop because it wouldn't start and it was a Pontiac only shop and they said carburetor was completely toasted they would have to overhaul it. So they did still it would only run as long as you kept pouring gas or starting fluid in the butterfly and then almost as soon as you quit pouring or spraying it would shut off. So he parked it in his side yard and never even opened a door or window or touched it. Then my parents had me. When I was born he made plans that he told my mom that it was going to be a father son project when i turned 16. That was 16 years ago January 6th.

So about 5 weeks ago while it was covered in vines, sticks, berry's, about a 5 inch deep puddle underneath it, flat tires, and cracked windshield he hooked a tow chain to it and pulled it into a extra piece of the driveway. He raised the hood, charged a battery over night, got a gallon of gas and we were ready to see if it would start. My dad poured gas in the carb, me being hyper i expected the worse and hoped for the best. Well he said try it j and amazingly it started the first time the key was turned. That's 29 years later after just sitting . Remember we live in the south part of Ohio so every year we have bad storms, a lot of snow, a lot of rain, and falling tree branches. Normal people would say don't waist time or money on the car. Me and my dad loving the car so much we did anyway. So it shut off after the gas he poured in the carb ran out. So he didn't hear the fuel pump working so he took it off tried to fix it and i told him don't worry about it. So i wake up the next morning to a new fuel pump. It took about 1 to 2 hours to put it in. Finally he poured some sea foam, some dry gas, some stabilizer, and fresh gas in the tank because it had half tank of old gas in it. So he finally said try it. So i did, it started up and now runs fine. We looked up my vin number it says original 1986 Pontiac firebird 5.7l v8 350. Also i checked last 7 vin digits that you match with the engine plant code then last half off vin number to see if the motors the original match to the car. The owner guide says 1986 5.7l v8 350 firebird right on the owners manual.

Also i was talking to a Pontiac representative at gm motors today and after about 2 an 1/2 hours of him beating around the bush he said there was an 86 firebird with a 350 in it that Pontiac made for less than 5 months if that. Also that was company information only that they haven't told anyone that the public knows of. So please do not comment hate on this i have worked on this for about 3 years doing nothing but researching the 86 firebird 350 myth well you all know that it really wasn't a myth. Thank you for reading. Please research it better than most people do it could take as long as it took me to get all this info but you'll never know if you don't try. Please do not leave hate comments on this please. This is like my whole lifes work so far being 16. Thank you for reading this blog.


wow thats a long winded response

all for you just to be told that sorry, the 350 was not debut in any thirdgen until the 1987 model year, and they never put a carbureted 350 into any thirdgen stock

if you would like to post up a picture of your RPO codes and vin i will gladly decipher it properly for you

Last edited by Caveman305; 04-22-2015 at 10:48 AM.
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Old 04-19-2015, 01:54 PM
  #119  
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Re: Is it a 305 or a 350?

lets just ban him instead?
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Old 04-21-2015, 08:07 AM
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Re: Is it a 305 or a 350?

They must have had "special" fuel pumps for the 305s, huh?
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Old 06-10-2018, 04:08 AM
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Re: Is it a 305 or a 350?

jack front of car up place stands under it . on either side of block is a cast three didget no this wil identify a 305 or 350 casting
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Old 06-11-2018, 07:19 AM
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Re: Is it a 305 or a 350?

hey just got my first car an 87 t top iroc z and me and my dad who knows cars well cant tell if its a 305 or a 350 what are some ways that i could tell what the engine is besides the vin number.
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Old 06-17-2018, 11:41 AM
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Re: Is it a 305 or a 350?

The simplest way to determine a 350 is to count the teeth on the flexplate/flywheel. If it has 100 teeth, it's a 350, and if it has 78 teeth, it's a 305. The 350 has more teeth to crank it faster with the higher compression. The lower compression 305 doesn't need to crank as fast to start.

(purple for sarcasim)



GM should have put some kind of numbers somewhere to identify their parts.
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Old 06-18-2018, 02:56 AM
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Re: Is it a 305 or a 350?

nice.please chime in if im wrong .thear is two difrent ring gear sizes .also two difrent bolt locations for the starter stagard and in line .all this shows is 1 or 2 peice seal eather 305 or 350 .just look up engine no on drivers rear side of block .how hard can it be
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