carb selection
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Now you've done it... Here we go with the Motorcraft vs Holley vs Edelbrock/Carter wars... LOL!
For a stock type engine, the Autolite/Motorcraft or Edelbrock are probably your best bet. For one that varies quite a ways from stock or for high-performance use, the Holley gets the nod because they are more 'tunable' for most of us backyard mechanics.
Now you have to ask yourself a few more questions. What are your realistic uses? How much are you going to ask your motor to rev? These questions, along with engine size, will help determine how 'big' of a carb you need. Generally, smaller carbs are better for street rpm usage where low-rpm torque and crisp throttle response are more important. You'll probably be more emissions-friendly and get marginally better gas mileage, too. Carbs with higher CFM ratings are best left for full-throttle applications, at the expense of part throttle crispness and power.
OK, let me state again that Ford used a 600CFM Holley on the GT390-equipped cars, and even the 428CJ got only a 735CFM. The higher-revving Boss 302s and Boss 351s used 780 vacuum secondary carbs. My 'mostly stock' BetaCat 351C-4V prefers a 600 over a 780. Even the 393W stroker motor I put together isn't under-carbed with only a 670 CFM vac secondary carb at 5500rpm. I tried a 780, but experienced no more power, yet I lost that low-midrange throttle crispness that I like on the street. You have a 289. A 450-500CFM carb is probably best unless you are all-out racing.
Trans type, rear gears and vehicle weight play in to what type carb (vacuum vs mechanical) is best for you.
For a stock type engine, the Autolite/Motorcraft or Edelbrock are probably your best bet. For one that varies quite a ways from stock or for high-performance use, the Holley gets the nod because they are more 'tunable' for most of us backyard mechanics.
Now you have to ask yourself a few more questions. What are your realistic uses? How much are you going to ask your motor to rev? These questions, along with engine size, will help determine how 'big' of a carb you need. Generally, smaller carbs are better for street rpm usage where low-rpm torque and crisp throttle response are more important. You'll probably be more emissions-friendly and get marginally better gas mileage, too. Carbs with higher CFM ratings are best left for full-throttle applications, at the expense of part throttle crispness and power.
OK, let me state again that Ford used a 600CFM Holley on the GT390-equipped cars, and even the 428CJ got only a 735CFM. The higher-revving Boss 302s and Boss 351s used 780 vacuum secondary carbs. My 'mostly stock' BetaCat 351C-4V prefers a 600 over a 780. Even the 393W stroker motor I put together isn't under-carbed with only a 670 CFM vac secondary carb at 5500rpm. I tried a 780, but experienced no more power, yet I lost that low-midrange throttle crispness that I like on the street. You have a 289. A 450-500CFM carb is probably best unless you are all-out racing.
Trans type, rear gears and vehicle weight play in to what type carb (vacuum vs mechanical) is best for you.
well basically, I'm looking for 600 CFM holley, I'm looking for street to moderate racing use, but I've been thinking of eventually putting 302 heads on it though so I want something I wont have to replace in a month.
What 600 CFM Holley models do you think will fit edelbrock dual plane 2121 manifold?
P.S what are the benefits of 302 heads over 289's? Is there any specs I should tell the machinist to make my engine breathe better?
What 600 CFM Holley models do you think will fit edelbrock dual plane 2121 manifold?
P.S what are the benefits of 302 heads over 289's? Is there any specs I should tell the machinist to make my engine breathe better?
NO BENEFIT TO SWAP FROM 289-302 HEADS.
This is the preleude to a whole build up thread. Stock 302 heads aren't any better than the 289 heads you have now. If, you have a fresh bottom end, new cam, then heads ay be appropriate, but not stock cast iron as a 'performance replacement'.
This is the preleude to a whole build up thread. Stock 302 heads aren't any better than the 289 heads you have now. If, you have a fresh bottom end, new cam, then heads ay be appropriate, but not stock cast iron as a 'performance replacement'.
oh I see...so the difference is in the block specs? is there an adapter or spacer that will allow my holley to fit my edelbrock intake? I know there is but I dont really know how to select it. It seems like its a hard match to make.
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I am running a Holley on my edelbrock intake, if you need to you can get a spacer plate that goes from the square bore Holley to a spread bore which is what most edelbrock intakes are, also in the case of my intake it has two sets of holes drilled so that either carb will bolt on, I am still using the adapter plate because I had it and I wanted a spacer anyway
The difference between the 289 and 302 is in the reciprocating assembly itself. The intake manifold and heads are the same, until you go aftermarket. Even then, they switch back and forth. A 289 fits a 302 fits a 289. You should not need an adapter to run a square bore carb on an edelbrock or holley intake manifold. Of course, a Ford guy wouldn't buy a spread bore for a SBF, usually...
How can you tell the difference between the two engines, were are the markings? I know that the heads tend to have a stamp between the rockers but what about the block?
I ended up getting a Holley 600cfm 4 bbl quadrajet square bore...
I ended up getting a Holley 600cfm 4 bbl quadrajet square bore...
well I told you I got the carb but theres some issues that I overlooked as a novice carb customer. The guy I bought it from is an a-hole and hasn't been much help...
The model number is 1850-S
I noticed as I tried to test fit the vacuum lines...there isn't any...only the distributor vacuum line. and fuel line. Usually the vacuum lines are on the bottom plate of the carb, but mine has none...do I need another base plate for my carb?
The model number is 1850-S
I noticed as I tried to test fit the vacuum lines...there isn't any...only the distributor vacuum line. and fuel line. Usually the vacuum lines are on the bottom plate of the carb, but mine has none...do I need another base plate for my carb?
No. There should be a ported and non ported vacuum outlet. So basically, the vacuum for the distributor advance goes on the side of the metering plate, and you can cap off the other one.
As far as your timing light goes, the light is powered by the battery, and the clippy deal goes on the number one plug wire. YOur timing marker should be on the drivers side of the car. You will probably have to crawl under there and sand/scuff the balancer so that you will be able to read the numbers. And you will need some white chalk too, so you can hilight all the numbers around where you want the motor timed.
As far as your timing light goes, the light is powered by the battery, and the clippy deal goes on the number one plug wire. YOur timing marker should be on the drivers side of the car. You will probably have to crawl under there and sand/scuff the balancer so that you will be able to read the numbers. And you will need some white chalk too, so you can hilight all the numbers around where you want the motor timed.
I meant that theres no outlets anywhere else on the carb other than the fuel line and the one in the metering plate for the distributor, so how do I hook up my PCV?
should I replace that PCV valve with an aftermarket breather?
I'll post up some pics in a minute....
should I replace that PCV valve with an aftermarket breather?
I'll post up some pics in a minute....
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Here are some pictures of an Edelbrock 2121 manifold with and without a Holley 1850-S carburetor mounted. Click the pictures for a larger view. This should be completely straightforward with no complications whatsoever. The carb shown is an electric choke Holley 1850, but the manual choke model is the same for your purposes. All the vacuum connections should be on the manifold and carb with no need for a spacer.
The first picture shows the manifold without the carb mounted. There are two threaded vacuum ports on the rear of the manifold. In this case I've used one port for the brake booster and the other for the vacuum tree for the headlights, etc., but you could do other variations on this depending on the fittings available.
The next picture shows the setup with the carb mounted. There are three vacuum ports in the Holley 1850, two in the base, and one from the primary metering plate.
The small port in the base is ordinarily plugged off. The small port from the metering plate goes to the distributor, either directly or through a temperature operated tree on the radiator hose neck. The large port under the vacuum diaphragm can go to the PCV Valve.
The next post shows a closer view of the smaller ports in the front of the carb, I ran out of allowable picture space.
John
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280 Posts
Here are some closer shots of the vacuum outlets on the Holley 1850 carb. The first is of the two smaller ports toward the front.
![Hollet Dist. Vacuum.jpg]()
The next shows the large rear port, usually used to connect to the PCV Valve. For some reason I can't post the next one in this post. Oh well.....
The next shows the large rear port, usually used to connect to the PCV Valve. For some reason I can't post the next one in this post. Oh well.....
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280 Posts
The larger rear port:
![Holley PCV.jpg]()
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Here is what I used for PVC hookup on my 351 4V. I have it on upside down so it turns towards the PVC.
http://www.cougarpartscatalog.com/bossspace.html
Randy Feuillerat
http://www.cougarpartscatalog.com/bossspace.html
Randy Feuillerat
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