carb for the boys truck?

[57sailplane]

hey guys,

My boy who just turned 16 is driving now. I have been fixing this truck up for him. The little Rochester 2 barrel that is on a 305 CID started acting up real bad. It dies and barley starts sometimes and is a total dog. I have a Holley 650 and performer intake. I know this is a lot more power and i hope he will be responsible. My first question is am i crazy, I mean i want my boy to enjoy driving like i did. I really want to put an edelbrock carb on it for him when i can get one. They are way better on fuel and are more drivable. My other question is this have any of you ran the 500 cfm carbs.. my calculator says 558 is the biggest i should run on the 305. i was planning on a 600 cfm but the calculator suggest it as being to big.

[Billla]

Any vacuum secondary 600-650 carb will be fine. The nice thing about vacuum secondaries is that they won't provide more air than the engine asks for. The primary venturies are still small enough to have good throttle response and driveability.

I would make a quick check of timing, etc. before jumping right on the carb as the problem if you haven't already done so.

The "classic" Holleys are very tunable, they just typically don't come tuned as close out of the box as the Edelbrocks and are comparatively harder to adjust vacuum secondary opening point and jetting. The Holley Street Avenger line is an attempt to make that better. With a little time spent reading plugs and doing some tuning - especially of the vacuum secondary spring - he'll have a nice running truck.

Nice looking truck - he's a lucky kid to have such a nice ride and a great Dad that's helping him get it together!

[JAKES 68GMC]

I know my dad had a 305 in a 79 C10 once. He had hopped it up a little with a (heres a bunch of names from the past: ) Holley 450 CFM Economizer carb, an Edelbrock SP2P intake, and dual exhaust with Royal Scott glasspacks. He said that was the best running engine he ever had. Not the most powerful one, but very responsive and fun to drive. He had 50 series tires on the back, and he said with a 2.76 rear end, that 305 would just smoke the tires right off.

Thats what he said, I'm just sharing my 2 cents worth.

[67ChevyRedneck]

Whether it's a 400 horse V-8 or a 120 horse 4 banger, any and ALL 16 year old males will try to see how fast their vehicle will go. I've done it, but I only had a 250 straight six and 3 speed

Hopefully he'll be careful and responsible. Paying for his own insurance and gas are always a step in the right direction

[RicksTrucks]

Agreed, all boys will do something. I put an Edelbrock 1406 on top of the 350 with headers in my son's 78 Camaro and so far all that he has done is dented up the passenger side a little while showing off coming into the gravel driveway - bouncing off a couple small trees - which he will pay for. Sometimes it is better to get them through this while they are young rather than them holding it in and then really letting it out later. I know they will enjoy it more if they like what they are driving. Sometimes it is just the knowledge that they can rev it up a bit, while in park, will keep them calm the rest of the time.

[Spanky_Pete]

I've run a number of 305s with that craptastic rochester 2bbl in my Impalas/Caprices. They may be rather anemic but will still put out enough power to get you into a lot of trouble. I rolled my first one at 16 racing some friends.

I have a Edelbrock 1406 on a '69 307 that's been mildly built, it makes more than enough power to enjoy.

[57sailplane]

those are the responses i was hoping for. as far as timing no i did not check that. i am pretty sure its not that just the way it acts. the hard starting is the main thing. it acts and smells flooded when it wont start. to get it to start you just wait until shes cooled down a while and she will fire up. and its been dieing at low rpm or idle. at highway speed she purs like a kitten. besides the boy wants to do it and i am letting him do the majority of the work. it could be a fuel pump but i would love to see him do this mostly himself and a fuel pump is an easy fix anyway. i have most everything to hop it up. carb, intake, hei comp ignition, and 1.6: 1 rockers.

well should i just keep the 650 holley or put a 500 or 600 edelbrock. its more for the boys concerns. the holley is a double pumper. the edelbrock would be a vacum sedoundary and worth the money in fuel.

[Billla]

Sounds like a vacuum leak more than anything; I'd be SURE of the timing and then take a look around with a can of carb cleaner It's a good chance for him to get it running RIGHT before he starts changing parts - diagnosis is one of the hardest things to learn...and one of the most important as you know.

With the 650 being a double-pumper, it's just too much for a 305 IMHO. Double-pumpers are race carbs, not street carbs I'd go for the 1406 600 CFM electric choke Performer; that'll work fine with his 305 and leave room for a fairly warm 350 if he heads that way.

[Nachos82]

If you find it is in fact the old carb that is bad, I suggest using the Holley since you already have it and that would save some $$$ on not buying an Edelbrock, unless you don't mind spending some extra cash on a new carb.

[jkade]

I went through 2 1406 edelbrokes and one holley 670 street avenger and they all suck. I rebuilt my quadrajet and it runs 5 times better than the others. JM2C

[MrC1]

As for worries about too much power - don't. A 305 in that truck won't be too hairy to handle. Nor will it win many races. It should be a good starter truck for him!

As for carb size - The calculator is based on 100% volumetric efficiency (VE) and is notoriuos for receommending on the small side. A 600 should be perfect for an average 305.

I wouldn;t waste the money on a new carb. Use the one you've got. Hey, at least Holley's are easy to work on!

[57sailplane]

thanks guys for all your advice. it is all apreciated. i will keep watching the poles just out of curosity. i will probably run the holley for a while we will see how he likes the gas milage..

hey mrc1

i could not help from laughing. your avatar says gute fahrt! dont tell me that stands for good fart! just kidding..

[Walts_restoration]

quadrajet baby, all the way, unless you need something bigger, than a 750 double pumper, or if your like my dad, get two 750 double pumpers haha

[bad6772]

Originally Posted by 67ChevyRedneck

Whether it's a 400 horse V-8 or a 120 horse 4 banger, any and ALL 16 year old males will try to see how fast their vehicle will go. I've done it, but I only had a 250 straight six and 3 speed

Hopefully he'll be careful and responsible. Paying for his own insurance and gas are always a step in the right direction

+ 1 one that

[70' GMC]

heck im only 18 and blew the engine in less than 4 weeks, I paid $1,412 for the engine to be rebuilt and just yesterday put on a new starter. My uncle fixed the 4 barrel by doing something to it and it doesnt have the get up and go it used to have but its a little better on gas. when I got the truck back I tried to melt the tires but that didnt work it instead cut off. I wanted get some bodywork done this summer well my green went into that itsy bitsy 350 hoping to get a 454 or better later on.

[70' GMC]

Originally Posted by Walts_restoration

quadrajet baby, all the way, unless you need something bigger, than a 750 double pumper, or if your like my dad, get two 750 double pumpers haha

uhh were do you get the quadrajet at????

[JAKES 68GMC]

If you make him do the work and pay for it, he will learn more about working on trucks and the value of a dollar. Besides, a 4bbl. 305 won't be too much for him in that truck IMO.

Thats what my dad did for me, I told him I wanted a souped 350 in my truck and he told me "You pay for it, you do all the work you can, and I'll help with what you can't do." So far its going pretty good, he doesn't have a penny in the swap so far and hasn't helped me too much, either.

[crm318]

you can find a qjet in a junkyard or at an autoparts store for 100-150. another vote for the quadrajet. it will put out the perfect flow for that engine and get better milage than the other carbs. gm put them on there from the factory for a reason.

[Billla]

Originally Posted by crm318

gm put them on there from the factory for a reason.

Yes; because they owned Rochester and they were cheap ;-)

[Brad]

FWIW, I've got a 1405 on my 250 and it ran fantastic right out of the box. I tried rejetting it leaner for my fewer cubes, but the engine really likes the carb the way it is.

[jkeady]

Quadrajets are nice... I have rebuilt tons of them. But of the tons I've set out to rebuild, I'd say maybe 1/3 of them were really good "basic" rebuild candidates. Float bowl leaks and throttle shaft vac leaks are the scourge of a QJet tuner and God help a noob who tries to set one up that's simply worn out. Yes, you can fix the float bowl, yes, you can bush the throttle shaft, but IMHO, if you're just working with a run-of-the-mill street truck, it's just easier to buy a 600 cfm Edelbrock and be done with it.

I'm not saying that the Quadrajet wasn't a good carb, it was a very nice design and if you can find a good one, it's a great mix of power and economy. But they're getting reeeeeal old and let's face facts: they just weren't built with longevity in mind.

[WorkinLonghorn]

But they're getting reeeeeal old and let's face facts: they just weren't built with longevity in mind.

I don't know.Mine is 38+ years old and runs REAL good. Last tank I got 12.2 MPG mixed driving that included some major (6,000Lbs.)hauling chores.That is about what an '07 2500 gets (6.0 Ltr). And still adequate power. I like those carbs as long as they are correctly "rebuilt".

[Shaffer4]

The truck I just got ('81 C-10, wrong era, yes, but similar setup) has a 305 with a 500 cfm Carter AFB (same thing as the Edelbrock). So far I have no issues with it, the engine is a stocker out of another 80's truck with an edelbrock performer manifold (and a Pete-Jackson noisy Gear-Drive ) running in front of a granny-low 4 speed and tall arse gears; 2000rpm at 55-60 in 4th... I've put ten gallons in the truck since I got it and got in the range of 200 miles out of that tank.

[1970bowtie]

my buddie has a 76 chevy lwb half ton with a 305, and a 2bbl,and there is no such thing as spinning the tires in that truck

[JAKES 68GMC]

Originally Posted by 1970bowtie

my buddie has a 76 chevy lwb half ton with a 305, and a 2bbl,and there is no such thing as spinning the tires in that truck