73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: m3talc0re on December 08, 2016, 06:41:30 am

Title: What size bolts are these?
Post by: m3talc0re on December 08, 2016, 06:41:30 am
I think they are the bolts that hold the carb to the intake manifold. I think the guy that worked on it before used whatever bolts he had and only has 2 or 3.. Anyone know the size these are supposed to be? Thread pattern and length?

Edit: carburetor mounting studs, is that what I'm looking for? I'll have to wait until this afternoon to take it off and actually look XD

Edit 2: This is an 83 GMC Sierra Classic with a 350. Edelbrock 1406 carb
Title: Re: What size bolts are these?
Post by: Bunkerbuilder on December 08, 2016, 11:23:36 am
You neglect to state if the carb is the factory quadrojet 4 barrel or an aftermarket carb and also what engine the carb is on.

So edit your post to reflect the information that is missing so the membership can intelligently address the question without being as vague as the  question is.
Title: Re: What size bolts are these?
Post by: m3talc0re on December 08, 2016, 11:57:02 am
I didn't even realize I left all that out -_-
Is that what they're called though?
Title: Re: What size bolts are these?
Post by: hatzie on December 08, 2016, 12:22:23 pm
A stock 4 Barrel Rochester Quadrajet is a Spread-bore carburetor. 
The Edelbrock 1406 is a Square-bore carburetor so it's definitely not a stock manifold.  At a guess it's probably an Edelbrock manifold.
The parts you're looking for are called Carburetor Stud Kits.  They're 5/16" with two different thread pitches and can be purchased short to very long.  The coarse end threads into the intake with fine threads that usually have a tapered end on top to make starting the nuts easier. Since you don't have a manifold spacer these short ones will probably do the job. https://www.amazon.com/Edelbrock-8008-Carburetor-Stud-Kit/dp/B000CN7134 (https://www.amazon.com/Edelbrock-8008-Carburetor-Stud-Kit/dp/B000CN7134)

If the rear studs need to be longer you can purchase them up to between 3" & 4" in length.

Get some assorted vacuum caps and replace the black duct tape the previous owner installed to cover the unused taps.
 
Title: Re: What size bolts are these?
Post by: m3talc0re on December 08, 2016, 12:28:51 pm
I forgot about that tape on there. Hopefully I'll have time this afternoon to take the carburetor off and actually have a look
Title: Re: What size bolts are these?
Post by: Irish_Alley on December 08, 2016, 04:18:47 pm
A stock 4 Barrel Rochester Quadrajet is a Spread-bore carburetor. 
The Edelbrock 1406 is a Square-bore carburetor so it's definitely not a stock manifold.  At a guess it's probably an Edelbrock manifold.
The parts you're looking for are called Carburetor Stud Kits.  They're 5/16" with two different thread pitches and can be purchased short to very long.  The coarse end threads into the intake with fine threads that usually have a tapered end on top to make starting the nuts easier. Since you don't have a manifold spacer these short ones will probably do the job. https://www.amazon.com/Edelbrock-8008-Carburetor-Stud-Kit/dp/B000CN7134 (https://www.amazon.com/Edelbrock-8008-Carburetor-Stud-Kit/dp/B000CN7134)

If the rear studs need to be longer you can purchase them up to between 3" & 4" in length.

Get some assorted vacuum caps and replace the black duct tape the previous owner installed to cover the unused taps.
 

could it be a stock intake with a carb adapter?
Title: Re: What size bolts are these?
Post by: m3talc0re on December 08, 2016, 05:43:03 pm
That's what it looks like. Carb looks dirty as all heck and the adapter looks like it restricts airflow...  It's a Mr Gasket cat.no.1932. And there's a dang bolt sheared off in one of the front mount holes...
Title: Re: What size bolts are these?
Post by: hatzie on December 08, 2016, 07:28:10 pm
I stand corrected.  That's a Spread-bore manifold.
The vacuum leak from that broken stud will not help performance.  Neither will the adapter.

I'm not a fan of cheaper Edelbrock and Holley replacement carbs.  They always seem to cost more in time and additional parts than the stock Rochester Quadrajets and they dont seem to work well without constant fiddling.  Quality reman Quadrajets can be had for around $250-$350 that just plain work for years with no drama.  Unless you're looking to wring the last 4hp out of your engine they are good performers and very reliable.  A better intake and exhaust will give you easier hp than a performance carb.

Sent from my SM-P605V using Tapatalk
Title: Re: What size bolts are these?
Post by: m3talc0re on December 08, 2016, 07:52:41 pm
I do have the stock carburetor.. When I bought the truck, he told me that it sat up for a while and had bad gas in it. I guess he took the carb off and had an edelbrock off another truck he had there to get this one running. Would I be better off trying to rebuild the Quadrajet?
Title: Re: What size bolts are these?
Post by: Irish_Alley on December 08, 2016, 08:22:22 pm
x2 on what hatzie said. right now you need to get the right intake then if parts are just thrown together like that (probably from the local parts store) they probably just grabbed a bigger carb and went with it thinking it will be more power. i would go with a quad also and get the timing set then hook the timing advance to manifold vacuum not ported like you have now.

for the time being i would try and get that bolt out put it all back together without any vacuum leaks in the base gasket like you probably have now. and set base timing around 16° then hook the vacuum advance to manifold vacuum that way its always there after it starts up.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=32085.0

http://forum.73-87chevytrucks.com/smforum/index.php?topic=31377.0

Title: Re: What size bolts are these?
Post by: m3talc0re on December 09, 2016, 07:52:04 am
Slow down Irish, you lost me at hello, lol.

Should I rebuild the Quadrajet or the Edelbrock? All over Google is mixed opinions about which is better.. I do know I can get the edelbrock rebuild kit down the road from O'Reilly's, but I don't think they have one for the Quadrajet. Would it benefit me to grind down the excess aluminum on the inside of that adapter to actually match up to the manifold's passages? Right now, it coveres up a good amount of it.

Edit: I found the numbers on the Quadrajet carburetor and it looks like it came from a buick or pontiac? It's a Quadrajet 17056264. Is that good or bad? I need to find where on that motor it says exactly what it is. The vin on the truck says it came with a 305, but it (supposedly) has a 350 in it. It's unknown where the motor come from atm.
Title: Re: What size bolts are these?
Post by: hatzie on December 09, 2016, 10:18:54 am
I agree with Irish.  Take it one step at a time.  That way you don't bite off more than you can chew.

Remove that snapped off stud and clean up the shavings.
Don't change the adapter
Re-install the Edelbrock 1406 with vacuum caps rather than duct tape, use the correct mounting studs, and use new gaskets on both sides of that adapter.
Set the timing to @ 16° with the vacuum advance hose disconnected and plugged.
Plug the vacuum advance into a manifold vacuum port on the carb...  Below the throttle plates or on an intake runner.
See how she runs.  Maybe the PO calibrated it close enough to make it run OK...  Considering the broken stud I doubt it but hope springs eternal. ;D

If it runs close to OK then you can start changing things.  Otherwise do some more testing and poking around.  Troubleshooting is not going to cost you $.

I'd get the Quadrajet re-worked if it's a regular M4ME or M4MC.  I wouldn't mess with a Computer Command Control M4MED Quadrajet.  Too many unknowns.  The electronics in the pickup, to make it work correctly, are unlikely to be unmolested and they may not be working properly even if they are unmolested.

What's the Quadrajet part number?  If you have a stock 1983 Quadrajet from a GM pickup the part number will probably be 1708xxxx or 17xxxxxx.  The last four or six digits will tell you exactly what carburetor you have. 

My comment in my last post stands.  I would install a working Rochester Quadrajet rather than mess with the Edelbrock or a Holley.

I pass on rebuilding some of the more complicated Two and Four barrel Carburetors myself.  The Rochester Quadrajet and the Edelbrock 1400 are not beginner units.  The parts count is way too high.  A Rochester 2G or 1G and my ATV and small engine carbs are easy.  Not those.
What I get for my $ with decent quality re-manufactured carbs is... operations like re-bushing the throttle plate pivot shafts that Joe Six-pack doesn't usually have the tooling or experience to handle (I don't have the patience to do it), the industrial outfits have access to nasty toxic chemicals like Methylene Chloride that actually melts varnished fuel & crud so all of the little passages are cleared out, the carburetor is completely setup & calibrated by someone that knows exactly what they are doing so I can bolt it on and go, and I get a warranty.
Title: Re: What size bolts are these?
Post by: m3talc0re on December 09, 2016, 11:27:18 am
Where can I send mine to be rebuilt? The Quadrajet I mean.

The Quadrajet I have is 17056264. Just a quick Google says it cane from like a Buick or Pontiac I think?

From what I've seen on YouTube, the 1406 doesn't look too bad. I may rebuild it myself to get my truck going  until I can get better. And yeah, the sheared bolt is coming out XD

Oh,  I don't remember if I mentioned it or not, but the edelbrock carb has gas leaking out of the side near where the fuel line connects. It's why I took it off. Should I rebuild it or just replace the gaskets?
Title: Re: What size bolts are these?
Post by: philo_beddoe on December 09, 2016, 10:40:26 pm
x2 on what hatzie said. right now you need to get the right intake then if parts are just thrown together like that (probably from the local parts store) they probably just grabbed a bigger carb and went with it thinking it will be more power. i would go with a quad also and get the timing set then hook the timing advance to manifold vacuum not ported like you have now.

for the time being i would try and get that bolt out put it all back together without any vacuum leaks in the base gasket like you probably have now. and set base timing around 16° then hook the vacuum advance to manifold vacuum that way its always there after it starts up.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=32085.0

http://forum.73-87chevytrucks.com/smforum/index.php?topic=31377.0
Hey i remember that famous rich weyand thread. I went through all that back when i was a rookie. Wait, i still am. Good teaching there.

A full rebuild on that qjet or get one here. I paid $195, great service, when i got mine it looked brand new. No problems since.

http://www.nationalcarburetors.com/
Title: Re: What size bolts are these?
Post by: m3talc0re on December 10, 2016, 04:56:38 am
I'll have to check them out. I bought the rebuild kit for the edelbrock, so I'll be working on that today.
Title: Re: What size bolts are these?
Post by: hatzie on December 10, 2016, 12:35:28 pm
x2 on what hatzie said. right now you need to get the right intake then if parts are just thrown together like that (probably from the local parts store) they probably just grabbed a bigger carb and went with it thinking it will be more power. i would go with a quad also and get the timing set then hook the timing advance to manifold vacuum not ported like you have now.

for the time being i would try and get that bolt out put it all back together without any vacuum leaks in the base gasket like you probably have now. and set base timing around 16° then hook the vacuum advance to manifold vacuum that way its always there after it starts up.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=32085.0

http://forum.73-87chevytrucks.com/smforum/index.php?topic=31377.0
Hey i remember that famous rich weyand thread. I went through all that back when i was a rookie. Wait, i still am. Good teaching there.

A full rebuild on that qjet or get one here. I paid $195, great service, when i got mine it looked brand new. No problems since.

http://www.nationalcarburetors.com/

I haven't bought a reman carb for about 10 years so I didn't have a recent enough recommendation to give me warm fuzzies.  I've had trusted suppliers fall off a cliff quality wise.

National was the outfit that provided carbs to NAPA when I bought my last unit that worked perfectly when I bolted it on and is still working fine. 

Another option is to ask the local hot rod guys.  They'll know if there's a local trusted carb guru.
Title: Re: What size bolts are these?
Post by: m3talc0re on December 10, 2016, 02:24:12 pm
Well, I'm not having good luck today. First, the bolt is still in there. I bought a craftsman extractor set and the dang extractor broke off into the hole I drilled. I'll have to take it to a machine shop I guess.

So i put sealant shoot on there and going to run it as is for now. Didn't rebuild the carb, just replaced that top gasket that was broken. Still leaking gas out. I don't know WTH the deal is..
Title: Re: What size bolts are these?
Post by: Irish_Alley on December 10, 2016, 02:54:42 pm
if that carb is a 1406 its a 600cfm. its not too bad but i think any "performance" from that carb will be taken away from that adapter and intake.
Title: Re: What size bolts are these?
Post by: m3talc0re on December 10, 2016, 03:09:25 pm
Maybe. It doesn't seem to be loose enough to let air through. At least until I can get it properly fixed. The adapter was on upside down before I think. It lines up with the carb and intake manifold now and isn't blocking things off.

And so far, knock on wood, there's no more gas leaking out. The float was way off. I didn't even think to check it before I put it back together...
Title: What size bolts are these?
Post by: philo_beddoe on December 10, 2016, 10:33:07 pm
Well dont fret over it, (i know, look whos talking). If the motor is in good shape and you dont want to spend a ton, you can always find a nice simple stock manifold and get a decent rebuilt qjet. All for no more than $300. I have done it.
Title: Re: What size bolts are these?
Post by: Irish_Alley on December 10, 2016, 10:40:22 pm
where was gas leaking out of? was the gasket wet?
Title: Re: What size bolts are these?
Post by: hatzie on December 10, 2016, 11:27:55 pm
I wouldn't pay more than $10 to get that stud removed because a replacement is cheap.  A used Quadrajet manifold should run you $25 - $30. That's about what they are running on Car-Part.com   
FelPro 1204 permatorque intake gaskets are $15-$20
A new 185°F thermostat and water neck gasket shouldn't be more than $15
If you don't have to worry about emissions checking the carburetor # just get the National Carburetor ND4650 that's listed for the 80's HD emissions 3/4 & 1 ton chassis.  It's on Sale right now... $269 including shipping.  You'll get $60 back when they get your core.  Don't ship the core back before you give the new one a good test run.
Title: Re: What size bolts are these?
Post by: m3talc0re on December 11, 2016, 06:31:59 am
I'd like to get a new intake manifold, but other things are ahead of it on my list XD

New tires, gotta fix or replace the speedometer, different steering wheel (hate the stock one, it's too thin), gotta figure out what's going on with the gauges and their lights, new sensor in the thermostat for the choke and probably a new thermostat housing. Etc..
Title: Re: What size bolts are these?
Post by: m3talc0re on December 11, 2016, 06:34:09 am
where was gas leaking out of? was the gasket wet?

It was soaked and dripping from the side the fuel goes in like crazy. I took the top off the carb again and looked at the floats and the passenger side was bent down way too far.
Title: What size bolts are these?
Post by: philo_beddoe on December 11, 2016, 07:37:43 am
Awww man...ya gotta love that classic skinny steering wheel. Its all part of the "classic" experience. That "feel" of driving a classic.

Make sure you keep it though, they dont make them anymore. Not even after market. Its one of those parts they just dont make, period!

Steering wheels, air cleaners, hub caps and wheel covers, etc..etc.  No reproduction!!