Carb sizing/choice? (and tuning..)..again..

Hi all,
-Firstly, I apologize for annoying you guys with another forum on carb sizing/choice. Thanks already!

Well After spending to many hours on Google researching carbs and carb sizing I'm just confused. It seems every man and there dog has a different opinion and I'd like to see what y'all actually run. Almost everything I have read or tried (formulas) lead to running something smaller than the general public. But then why do so many people run what seem to be way to big?

Anyways I'd like to here your guy's opinion for my set up specifically.
Its a 351W
-Currently a 750cfm Holley with mech secondaries.
- Eddlebrock performer 289 intake
-A cam, no idea on the specs or brand, but guesing Erson from the stickers?)
-Stock exhaust manifolds.
-STREET DRIVEN. I do enjoy a lead foot but practicality is most important
-I'd like to hear more than just the CFM but specific carbs. It seems even with a specific cfm target there are choices out the ***.

Thanks guys!

 

Stock exhaust manifolds are the first indication that your carb is a little on the large side. The better an engine breathes, the more fuel it can handle. Within reason.

Vac*** secondaries are a bit more forgiving than mechanical secondaries.

 

Also it really seams to bog down under acceleration recently? Any ideas...


And a little history...Just bought the truck ('56 F100) Seemed to be some kids toy. Most of it seemed to be done in the "bigger is better fashion" and not exactly neat. As my Dad says its wired like a Christmas Tree. Its more than a mess but $100 for a ***led runner I couldn't say no.

 

And yes the Stock exhaust is really my only option at the moment. This is popular subject a**** '56 f100 owners with a 351 swap. Without rack and pinion conversion or m***ive modifying to steering your only option is custom headers. Also The engine mount doesn't allow height to the headers at all. So custom headers will come someday; hopefully soon but that's money and time. Both currently are slim..
thanks!

 

Do yourself a favor and find a vac*** secondary 650 holley for it. Buy a rebuild kit and go through the carb. You will have a much more enjoyable driver.

 

289 intake won't bolt up to a 351W. The 351 is wider and takes a different intake. So you either have a 351 intake or (probably) a 302.

 

ruh roh raggy.
More surprise's lol
Beware my norm is British Cars, never had one a big 'merican lumber wagon before so my experience is nill. whats the best way to identify this stuff?
The only thing I know foreshore is that the ****** is c4 out of a 75 torino. (got that from the numbers.)

 

I'm with Larry, If its got a Performer 289 on it, you have a 289/302 there, not a 351W. If its got a '74 C-4 in it, my bet is 302.

 

I skipped right past the performer 289 intake. As already posted, you have a 289/302


Scratch the 650. Find a 600 cfm vac. secondary Holley.

 

if it is a good runnin 351, go 82 squared on the jets. Perhaps a set of good headers are in your future. DONT castrate the eninge with a 650 cfm carb.

My 1982 302 ran a 850 dbl pumper 84 sq. She ran like a scalded cat.

I am a big fan of pluging the power valve for street / strip drivability, but you will have to bump the jets. Perhaps 82 P 86 S...

If it bogs at the initial punch, you need to adjust your accelerator, and when your accel pump comes in. If it continues to bog after that but not on at the punch, its either a low float bowl, weak fuel pump, or weak ignition. CHeck your plugs to see what they look like. If they are black an sooty, you have a weak ignition.

I thought the big torinos had c6's

 

Before spending money on a different carburetor, you need more answers:

First, the Ford fellows here seem to believe you have a 289 or 302 instead of the 351. FIND OUT FOR CERTAIN.

Next, you have an unknown cam... it needs to be known. Find someone local to help you "degree" the cam so you know what you have.

And a compression test would tell you the approximate compression ratio for your engine.

And I am sure the Ford fellows know, but I don't; what "footprint" is the performer intake? Squarebore or spreadbore?

Something to consider: which brand carburetor do you feel the most comfortable modifying, or learning to modify? You have a better chance of winning an argument with the IRS that getting a "boxed" carburetor with a perfect calibration for your combination.

And finally, you asked why many purchase a carburetor that would seem to be too large. I posted the following in a similiar thread on this forum right before Christmas, hence the Santa reference:

There is an old story here in Missouri about a young hillbilly who had never owned a pair of shoes. On the young man's 17th birthday, his uncle offered to buy him a new set of boots as a birthday present. So the young man walks to town, and later walks home wearing a shiny new pair of boots. The uncle asks him what size they were. The young man replies "Well, the salesman told me my correct size was 9, but 10's felt SO GOOD, I bought 11's"!

More often than not, carburetors are bought using the exact same "logic"

Even Santa got in the act! Eight reindeer were insufficient; he had to have 9!

Jon.

 

Sent you a pm,a 750 mechanical secondary is overkill on a 289-302 which probably accounts for the bog, a 600 Vacuum secondary would be more street friendly and better on gas mileage to boot and will work better with the Performer Intake.Probably would not be a bad idea to look into a Rebel Wire harness to fix the wiring issue,Rebel is a H.A.M.B. member and gives a 10% discount and great customer service if you need help.A HEDMAN Header 88400 should fit without issues.

 

A 750 would be ok if it were vacuum secondaries.

 

I think Ford put 585 cfm Holleys on the last carbed Mustang GT 302's. They ran pretty good for the time.

 

Forget the Holley. Get a 650 Edlebrock with mechanical secondaries. Easiest carb to change jets,metering rods and secondary timing. Set engine timing for proper elevation and enjoy. Holley carbs are a major pain in the ***!!!!!!!!!!!!!!!!!!!!!!!

 

Only if you don't know how to tune one...

 

For that combo a holley 670 street advenger va*** sec will run perfect !! had one on a earlier set up loved it right outta the box

 

X2 The Holley vs Carter/Edelbrock debate will go on forever, kind of like which one is better in the sheets a blonde or a redhead,if you can't turn em' on you won't enjoy the ride

 

When your dealing with a piece of **** that was cobbled together from who knows how many carbs, then yes they are a pain in the ***.

Start with a original Holley and learn how to tune it, and you will be very happy.

 

Id take a quadrajet over a Carter/Edelbrock any day.

 

Just a thought could it be he has a 302 with 351 heads? Then the 289 intake would work.

In sizing a carb I was always told that a motor is nothing more than an air pump. It will only draw what CFM it needs. And yes I would think a 750 would be on the big side for a SBF. It all depends on what kind of RPM the motor will turn and how you want to run it.

 

me too as a rule, but putting one on a sbf is heresy. You will anger the gods, and verily, the rath of Dearborn shall decend upon your head...

 

Would it be OK to put one on a 429?

Jon.

 

smart aleck... A buddy of mine almost ****ped when he saw an SS legal 460 with a thermoquad on it...

 

You evidently read that Edelbrock Performer 289 somewhere, probably on the intake. If so, you do not have a 351, but a 289 or 302. If that is the case, a 750 is way too much carburetor. A 500 or 600 cfm would be much better, and personally I love Edelbrocks. You bolt them on and forget them.

Measure across the top of the intake to how wide it is and get us that measurement. I have both 302's and 351 W's in the shop and can measure them for you.

Don

 

Aman!!!. Ain't that the truth...
Had a combination of all three.... Not all at the same time though...

As much as I wanted to...

 

All joking aside, LOTS of non-smog performance Ford 302's and 351's were factory equiped with Carter thermoquads. Most enthusiasts are simply unaware of these.

Jon.

 

Personally, I think the Thermo-Quad is about the most under-rated carb around. I've built a few over the years, always found them to be good WOT performers with EXCELLENT fuel economy. Too bad there isn't more parts support. Knew about them on the 385's didnt know they were put on small-blocks as well. Any day I learn something new is a good day.

 

The gods already dislike me. Ive put Chevy engines in Fords.

 

I got a chance to measure the 302 intake vs the 351 intake today at the shop. The 302 is about 9 inches wide and the 351 W is 10.5 wide, so you will be able to tell for sure which one you have. I measured at the widest spot on the manifold across the front.

Don