305 carb issues

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Rusty Nail

Full Access Member
Joined
Jan 29, 2015
Posts
9,806
Reaction score
9,728
Location
the other side of the internet
First Name
Rusty
Truck Year
1977
Truck Model
C20
Engine Size
350sbc
Yeah...

xc_hide_links_from_guests_guests_error_hide_media

Yeah seriously.

But I used to be an auto mechanic, i'm not a parts swapper.
You can put lipstick on a pig, or butter on a turd, heck you can even build a house of cards on sand...but if you put a pile of high dollar, shiny new mismatched parts on top of an 8.3:1 305 with #201 (76cc) heads, it will not perform well and that time and money will have been wasted.
It wont even look good.

You asked this hotrodder's opinion...not my fault you dont like it.. Of course, then again i'm pretty sure I stick to the facts (thats my job now see?) - pesky, troublesome , facts.
xc_hide_links_from_guests_guests_error_hide_media
And now we know what you are about. Your concern is neither performance nor gas mileage, you want to waste money on shiny new parts that will perform.poorly - rather than FIX IT.

I'm no help there Tom, you're talking to the wrong guy. But see the thing is, there are THOUSANDS OF EYEBALLS that will read my reply and it aint about you.
It's about the truck and the audience.

SO, since you can't stop me, i'm going to finish my recommendations for the other viewers because yes, I take it seriously and like to think I know wtf i'm talking about
OR I WOULDNT SAY ANYTHING.

damn. See what I did there? Pretty slick!!

Tell em Pedo! Hit em with the eyebrows!
:pedobear:
Yeah baby!

Since I am an actual mechanic and im under no obligation to sell parts to pad the ticket, I mostly sell gaskets and work on the clock = not flag.
**** your labor guide, I dont care what it says. I'll tell you what it cost when im finished if you want it back. LoL.

IF ! Tom. You were about fixing your truck, we will work with #601s but if you have 201s..that's almost a hard stop.
Lower your expectations or change cylinder heads because it will always be painfully slow.
Lol sadface :(

Pesky facts.
Edelbrock 600 isnt big enough for a 305.Buy at least a 650. 670 even.
Oh ****.one of those is a Holley.o_O
Well, the other one could be what you already have but its impossible to tell with your ****** attitude and unwillingess to participate in your own success.

Either way we have to change head gaskets if you are about going fast or getting better mileage.
Shims. Copper shim head gaskets.
You WISH you had 601s but you dont.
Youve got 201s.that camshaft is really very bad. 305s 76-80 is a piece of ****.
You could spend a bunch on new stuff or you could be a cool hotrodder and run different factory parts. But thats not what youre about.
Again,nothing personal.

Swap to copper shim head gaskets and dont tell anybody youve got 201s. Lol.
MUST. buy aftermarket rocker arms though.
Factory ones are garbage.
Rebuild that Quadrajet IF it's a 650. Those are AWESOME carbs.
Pick up an aluminum intake.
Almost ANY will out perform the cast iron pile you' ve got now.

$100 to change head gaskets - at that price you've got to do it yourself.
Shop around. Craigslist or ebay or this MSB even and buy a used aluminum intake manifold.installed? $100 all you too.
$100 buys Comp Cams Magnum roller tip1.5 rockers. Also on you.
$100 buys a carbkit,fuel filter and associated gaskets to rebuild your Quadrajet. You can do it for that
You can EASILY find a pair of used maybe new headers for $100.
$100 buys other pieces associated with paying an exhaust shop to connect them.

$600 bucks.

Will whup the tar out of some jagoff punk that spent $600 on getting a shiny new carb and intake installed on the same 305 u got in the next lane thats fixin to get his ass whupped.

But hey, it depends on what youre about.
When you pop the hood because nobody believes it's a1980 305.look it says 50 right on it. The stock engine.
No bling Tom. That dont make it go no faster or get no more mpgeez.

You've got.to.have new shim.head gaskets.
Sure theyre shiny before you cover em up with cylinder head..nobody will see your rockers either. If you source a 1983,4,5, or 6 GM factory aluminum intake nobody would look twice if you dont clean the outside too good - youve only got headers.

That's what I used to be about. You wanna run em? Il take your money. Look Its a 305.
How much you got in your pocket?

But im an actual mechanic ,not a parts swapper. I dont hold appreciation for covering ignorance and apathy with shiny stuff.

How much were you plannin to spend?

It took me one hour to write this reply.
 
Last edited:

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,051
Reaction score
1,853
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
GM used the Quadrajet in various vehicles for about 20-25 years, and they were all tuned for the engine in that specific vehicle. They are not all the same.

Unless you have the number and application of the Quadrajet, tuning is just a shot in the dark. If yours was original to your 305 and you tune it to near original specs, it will probably run very well. However, over the last 30 years quite a few folks have probably tried to tune it and gotten it thoroughly screwed up. It might not even be put back together right so all the linkage works. A good rebuild kit and other parts (shaft bushing kit, electric choke conversion, etc.) will run you close to $200, but may be worth it to you.

Like every other project, estimate your budget first. If you really want a strong engine, start out with planning for better cylinder heads and more compression. If you just want a reliable engine that is a little better than the original, then just swap intake and carb, and add headers and good exhaust. Crank up the base timing and timing curve to get a little more out of the original low compression heads and it will work fine.

Bruce a
 

Tom Sawyer

Member
Joined
Jun 6, 2020
Posts
47
Reaction score
86
Location
Dracut, MA
First Name
Tom
Truck Year
1980
Truck Model
C10 Silverado
Engine Size
350
Thank you so much for a clear, concise, explanation without the drama and blather. I mean it, you are a breath of fresh air.
Tom
 

gotyourgoat

Full Access Member
Joined
Mar 27, 2014
Posts
2,117
Reaction score
3,418
Location
NRV Virginia
First Name
gotyourgoat
Truck Year
1984
Truck Model
c10
Engine Size
smokin' 305
Thank you so much for a clear, concise, explanation without the drama and blather. I mean it, you are a breath of fresh air.
Tom
A breath of fresh air would be acceptance of a 305 being a 305 and that GM used quadrajets on damn near everything from '65 to '90. Beginning and ending few years with lesser numbers of course.

Maybe my comment was too succinct. Maybe I'm still a little upset my truck was said to have a 350 which turned out to be false. As someone with a 305 which has a bunch of add-ons I can assure you Brown has been accused of a lot of things but fast is not one of them. Stock turn key instant start up so you can jump in and go in any weather is not it either.

Or maybe it's the rash of threads lately where someone has accused a quadrajet of something and replaced it with x, y, or z and now they have issues like fuel pouring everywhere, no idle, no way to run lines without a dozen connections/fire hazards, exploding mufflers, fuel pressure regulators, terrible gas mileage, vaccum accessories no longer working, binding cables, burnt up transmissions and that's just off the top of my head I'm sure there's many more.

Adding the fact that you live where the weather changes and have a clean original squircle with 53k. Keeping it original is really the way I would want to go with it. So sending the original off to be rebuild or using it as a core for one of the same would be my suggestion. Unless you want to put that quad in a box for safe keeping and put efi on it?

Also something to keep in mind, 650cfm is less than what the stock quad is capable of preforming.
:happy160:
 

Rusty Nail

Full Access Member
Joined
Jan 29, 2015
Posts
9,806
Reaction score
9,728
Location
the other side of the internet
First Name
Rusty
Truck Year
1977
Truck Model
C20
Engine Size
350sbc
A breath of fresh air would be acceptance of a 305 being a 305 and
Maybe my comment was too succinct. I'm still a little upset my truck was said to have a 350 which turned out to be false.
:happy160:

I bought a Blue Ox once with a "350" in it and it was actually a 267.
?
A motherfvckin 267 - that really happened.
But its all about the blather , its how this board stays fresh.
And thats why you like it.


xc_hide_links_from_guests_guests_error_hide_media
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,743
Reaction score
6,784
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
Remove the carb and replace the part beneath it with a 350. Then, throw carb in trash and install Edelbrock Pro-Flo 4.

Remember this, Rusty Nails career resides in a junkyard. Take it for what it's worth.
 

Rusty Nail

Full Access Member
Joined
Jan 29, 2015
Posts
9,806
Reaction score
9,728
Location
the other side of the internet
First Name
Rusty
Truck Year
1977
Truck Model
C20
Engine Size
350sbc
Lololo

The 267 DID have #416s on it...:shrug:
3.5" pistons yeah but it wasn't all bad.

TINY valves too though, nevermind.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,746
Reaction score
11,347
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
You know I read this thread the night it was posted, but I could see where it was going so I've kept my mouth shut for a little while which is weird because I usually jump right in to carb discussions. I guess after the last carb / regulator thread I just didn't want to be in the middle of the drama, yet I think you or someone else that reads this thread might find some value in what I have to say so here it goes. You get strong opinions on carbs because people have strong opinions about what is best. And we all have different back grounds. Some of us are current or former mechanics, others are racers, others are back yard mechanics, and we have had different experiences though the years. Personally on a 305 I'd go with the Q-jet, why because it's what the engine is suppose to have. I think the main reason why some people don't like the Q-jet is because they don't understand them. They are a tough carb to rebuild but once rebuilt right it'll give years of reliability. Plus if you slap something else on there your going to do quite a bit of tuning, and I don't mean just with the screws on the front, you maybe changing jets and / or metering rods / power valve to get it right. Will an Edelbrock or Holly run that 305 right out of the box sure, but it won't be tuned optimumly. Though I don't see where it says what your goal is I'm going to take a guess that you would like to squeeze as much power out of the 305 as you can, and if it were me I'd want the best mileage I can get to which leads me back to the Q-jet. It's not like the factory Q-jet is undersized for the motor like some of the small block mopars were with the 2 barrels. I just can't see anything other than the Q-jet being best for a 305. And lets not even get into the fact that he may have to do something to control fuel pressure like installing a regulator or special pump, after installing another brand of carb. Figure $100 - $150 extra into your budget for that. We also did not talk about what tranny this truck has, if it has the 700R4 and you change carbs you got to make sure the TV cable is set up correctly or you'll burn up the tranny, and more money / time to install or fabricate a bracket.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
4,224
Reaction score
6,192
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Burning up trannys isn't cool.Your gonna get the. LGBT something or other police on us.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,746
Reaction score
11,347
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
Burning up trannys isn't cool.
After I posted I went back and looked at the OP's profile and his truck is an 1980 so I don't think the 700R4 was out until 82, but still it might save someone else that reads the thread in the future.
 
Last edited:

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
4,224
Reaction score
6,192
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
After I posted I went back and looked at the OP's profile and his truck is an 1980 so I don't think the 700R4 was out until 82, but still it might save someone else that reads the thread in the future.

No worries I don't think the LGBT really have special police.
 

Latest posts

Forum statistics

Threads
42,337
Posts
913,908
Members
33,837
Latest member
Mousta5
Top