Stock Intake

[Redneck86]

Im wonderin what the stock in take on my truck is spread bore or square bore. Im pretty sure im gettin a Holley 2300 500cfm 2 barrel for my truck, and need to know what style adapter to get. I think its a spread bore but im not 100% sure.

 

[Broncobill78]

Every stock intake I've ever seen has been a spreadbore. Incidently that's *why* most factory 4-bbls seem to get better milage than their 2bbl cousins, the primaries on a 4bbl spreadbore are actually smaller than the primaries on a 2bbl, so unless you drive around with your foot in it most of the time (meaning you're able to keep the secondaries closed) you're actually better off with a 4bbl. Sorry, got to rambling a bit, bottom line is that you *should* have a spreadbore if the intake is a stock 4bbl.

 

[Redneck86]

Its stock and the Edelbrock is sittin on an adapter, Im gettin a 2300 Holley 2 bbl so it wont flood as bad. My buddy up here has a F150 that has one and it never stalls, floods, or hesistates at all, least not while im with him. Plus a 2bbl is easier to tune. I dont think my truck will have any power problems with a 500cfm either.

 

[BLADE262US]

Every factory ford intake Ive ever seen has been a squre bore . The spread bore was a GM thing . I have a couple factory 1986 351 ** intakes here and there both square bore . /emoticons/[email protected] 2x" width="20" height="20" />

 

[Redneck86]

Sweet thanks man, thats what my truck has is the 351HO, im gonna put a Holley 2300 500cfm 2 barrel on it so i need an adapter.

 

[Broncobill78]

Really ? That's interesting. when I was building my 460's I wound up w/a bunch of factory 4bbl intakes and every damn one of them was a spreadbore. Not disputing anything, just wondering if it was maybe a big-block/small-block sort of thing. I generally put the engine together & used an adapter & a square-bore Holley until I got the cash together to buy another Predator. I honestly never saw many 4bbl small-block intakes but I *DO* remember having a stack of spread-bore BB intakes on the shelf.

I DO remember buying a few square-bore adapters to run w/the carbs. I haven't yet bludgeoned *those* brain cells to death. When I googled "ford 351 spread-bore" all sorts of info came back & from what I can tell after a quick 20-30 minutes of reading is that they seemed to offer plenty of either, it just depended on the year & the options package.

 

[Redneck86]

Well damn, looks like im gonna have pull the f*ckin carb off anyway and see. That kinda sucks but it beats orderin the wrong adapter and sendin it back for another. Thanks for the help anyway.

 

[Broncobill78]

Well, I guess there's never an easy answer around when you want one (sorta like cops <Grin> )

One of the interesting things I noticed when looking into it was that the 351HO engines were spreadbores. I know that in 87' the standard 351 was dropped & only the 351HO was available (as far as Bronco's went anyways). Might well be that the standard 5.8's were squarebores and the **'s were spreadbores. I guess there's enough damn minutiae here to make someone think this was a GM forum. I find that *more* than a little embarassing.

 

[Redneck86]

Well like i said, i guess im gonna take the carb off and see and be *certain* what it is when i order it. Right now the carburetor is sittin on whats either a spacer or an adapter, i know that the Edelbrock is a square bore but the linkage on the carb also had to be raised above something on the mainfold. So i im just gonna play it safe here so i dont f*ck around and get everything torn apart and find out ive got the wrong adapter /emoticons/[email protected] 2x" width="20" height="20" /> Dont here many 17 year olds say *that* do ya?

 

[Broncobill78]

Dont here many 17 year olds say *that* do ya?

Awww, DAMN boy, now you're just being spitefull. I've got KIDS that are almost older than you. Now I know you didn't get the answer you wanted but that's just no reason to go & get MEAN about things. Damn.What's next, Rogaine jokes ?

 

[Redneck86]

Im just sayin that *most* of my friends out here are the kind that rip everything apart and dont know how it goes back together, or they order the wrong parts then dont have a ride for awhile while they wait for the right ones. Then im the one they call hoping i know how to fix it. Im not trin to be mean im just say most of my friends from 16-20 are like that. /emoticons/[email protected] 2x" width="20" height="20" />

 

[Justshootme84]

I'm with Blade on this one, even my 84 351W H.O. was a square bore for the 4-bbl Holley. I still think you'll be bogged dwon with a 2-bbl, but hope you prove me wrong. If you don't like it, I have a spare HLY 4180 4-bbl that you can try, JSM84

 

[Redneck86]

Never mind ill send you a PM about it.

 

[Justshootme84]

Yes, the Holley #4180 is the stock carb for the 84-86 351W H.O. Since you're planning to sell your Bronco to get an older 78/79, just stick the 2-bbl on there. JSM84

 

[Broncobill78]

Well, with all due respect to Blade & JSM, it *must* be a bigblock/smallblock thing. Now everything I've READ tells me the 351HO's are spreadbores but I really haven't built any Clevelands or Windsors and I never really paid any attention to the Milford & 400 intakes I removed since I knew they were headed to the circular file. HOWEVER, I *did* know good & well that I'd had a stack of stock spreadbore 460 intakes sitting on the shelf for several years and that every 460 I'd build had showed up in the driveway as an OEM spreadbore. Everyone had me starting to doubt myself to the point where I actually went into the kitchen to count JUST how many beers were left out of that last case. After assuring myself that those memories *weren't* alcohol induced I went to the bookshelf with my prized & trusty refrence library & confirmed my original thoughts. While the exploded engine diagrams DID show the intake, the carb pad wasn't shown in enough detail to be convincing. The carburator section, however, was unambiguous. The factory 460 carbs were *clearly* spreadbores. Perhaps some or even all (if *everything* I've read about the H.O.'s was wrong) of the smallblocks were squarebores but the big blocks were spreadbores.

 

[Justshootme84]

Even that carb looks like a squarebore to me?

 

[Redneck86]

Well i think know a easy answer to this question, at least for the 84-86 351HO. JSM is your holley 4180 a squarebore? If it is then my intake *must* be a squarebore. Just thought id throw that out there.

 

[Broncobill78]

Even that carb looks like a squarebore to me?

Ok, wow, now you're just fu*king with me right ? Evan at 4:30am this thing looks to me as though it PLAINLY a spreadbore. Print out the page & use a ruler or better still a caliper. Unless you're just *trying* to mess w/my mind. The right-hand photo on 24-26-12 doesn't CLEARLY show you that it's a spreadbore ? Maybe click on that little square looking thing with the arrows in the lower right hand corner of the page, it'll make it larger. I *specifically* went with the hi-res scan so folks could see what I meant. And you don't see the *exact* same difference in bore diameter on 24-26-13 ? WOW. One of us needs to go back to the *****. ******** aside, you *honestly* see NO difference in the bore diameter ? ALL FOUR of them look the *same* to you ????? Tell me, because if so I'll call my Doc & tell him I need better meds. Wow, I need to go look for some ******.

Am I *really* the only guy who sees this ? Please, someone, ANYONE. C'mon, you're just f*cking with me right ? Are you *really* going to make me go out tomorrow & buy a digital caliper ? Please tell me you're not. C'mon, everyone already *knows* I'm not very tightly wound, don't do this to me.

 

[Justshootme84]

Redneck, yes the Holley 4180 is a squarebore, so the intake is, too. 100% sure on that.

BB78, I honestly can't tell from the 3 pics you posted where it says anywhere what type of carb base it is. But from the 2nd pic, it appears to me that the base is square. That is, the four holes to mount the carb have a square pattern. The only "spreadbore" factory carb I'm aware of as Blade stated is the GM quadrajet.