[font size="1" color="#FF0000"]LAST EDITED ON 11-Aug-01 AT 04:19 AM (EST)[/font][p]I scanned the message board and saw a lot of tips about the edelbrock carb, and a lot of you who swear by the motorcraft 2bbl.
But i did not see anything about putting the 4 to 2bbl adapter onto the edelbrock.

I just bought the performer intake for my 390 on a 68 f250 cs.
(Hey HiMe, did you ever get my email?) I'm sure that the edelbrock carb would be the best combo, but there were two reasons for not buying it yesterday: i am trying to watch the budget; and the 2v carb I have now is 'new' or at least rebuilt. it was put in last month and runs fine.

so, would anyone advise me NOT to use the adapter? if so, would it do harm if i used the adapter for 6 mo or a year?

Finally, most of you agree that a spacer helps protect the carb from the extra heat dissapation from the aluminum. (I do NOT live in cold climate and i currently have the "hard start when hot" problem). I am assuming a spacer would look something like the stock spacer on the 390 that had the water passage and fit under the carb. So my question is: would the 4 to 2bbl adapter serve as a spacer?

Oh, one last beginner's question: edelbrock says the performer will not match up with a motorcraft spread bore carb. what is a spread bore carb? do I even need to worry about it for a 68 390?

As always, thanks for any help. Most of my questions from the last six months have been answered without my needing to post!

 

Mike, you might want to go over to the FE Big Block forum and about 7 down is a large thread "390 tuning" Bob Sprowl wrote a very nice piece on carbs there that could be of interest to you.

John

jowilker
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66F100s Rule
In the cool still quiet of night you can hear chevies rusting away.

 

Thanks John. It is a good post, and I humbly admit I don't understand every last word of it - I really admire the carb gurus.

However, let me be clear. My question is about any advice or warnings for using the 4 to 2 bbl adapter, not so much about which is the better carb.

Also, if anyone was wondering, I was not looking for extra power or anything special. My main goal is to seal up that rear intake leak, and since this is the second time, I am not going to try to place the stock mainifold alone, without a hoist, in the chassis, perfectly lined up in one shot, again. <grin>

 

Be sure to include some RV silicone gasket sealer and let it get tacky before you attempt to set the intake. You should be ok with using the 2 barrel carb.

John

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66F100s Rule
In the cool still quiet of night you can hear chevies rusting away.

 

The adapter I have in my junk pile is not the highest quality piece, but it might work okay. What would concern me is that the heads of the (top) carb studs are inside the manifold and could cause an elusive vacuum leak.
Eric

 

Yes you can use the 2 to 4v adapter. Yes you are correct in that it will also serve as a spacer. Edelbrock carbs are square bore mostly so the intake is set up for them, vs. spread bore. Basically they have a slightly different bolt pattern, but there is a spacer available that will compensate for that, but you don't need to worry about that. You are putting a 2v onto a 4v intake so just get the adapter and you will be fine.

chris
79 F-150 Ranger Lariat, 2wd, RC, LB, 460 (intake, headers, cam), C-6(shift kit).

79 mustang (work in progress...its just slow progress)
98 Chevy 4x4 (work truck)
95 Lexus SC300 (wife's baby)

 

thanks for the vote of confidence on the 2bbl. if it performs poorly, i will dish out for the edelbrock 4 bbl.

well, I was indecisive until the last minute, but I threw away the cork front and back seals and went with RTV only. i also let it set up a little, and a least judging from the front, it looks like the "waiting" technique really did minimize the oozing.

i really wanted to do it right this time. I had done it once with the cast iron intake, then my mechanic put some new heads on, so he was the last to touch it, and man, the rear seal was a mess, you could drive a truck through it!

so i took my time, went over everything, spent the whole day, and bam! forgot the stupid radiator bypass! so now I have to dismount the whole fan and water pump to get that tube in.

i can't believe you just tap that bypass tube in? any tips for a sealant? locktite? silicone? nothing?

also, i know a couple of you had the stock carb with the water passage. that "spacer" (not really but looks like one) had a vacuum inlet; so by not using it, now i'm short an inlet compared to what i had before swithing the manifold, which was: carb vacuum to distributer, 5/8 threaded to 3/8 nipple for the transmission from the manifold surface, and both pcv and brake cylinder to the "spacer".

so it looks like now i have to run the brake cylinder, pcv and transmission all off of the one inlet on the manifold. does that sound right? am i not seeing an vacuum inlet somewhere?
any problem with running all three off of the same line?

thanks again to anyone with the patience to read all that and shoot an answer to me!

 

I recently helped a friend w/ an engine swap project. Now this is a Chev 327 but a related deal. The Manifold was an edelbrock performer spreadbore. Most GM's w/ 4V had Rochester Qjet carb which is a Spread bore... that is the area the secondaries empty into is wider than the forward part the primaries dump into. A spread bore manifold has kind of an oval/kidney shaped opening rather than square. Well the engine had a Carter AFB square bore carb on it. That Carter is essential identical to the Edelbrock...both made under license from Weber USA. Anyway we got a Mr Gasket spacer/converter. It was a pretty slick installation w/ nice fasteners. I think I've seen Mr Gasket brand 2-4v converters as well. I think a 2V feeding a 4V manifold through a spacer is probably alot better than a 4V being fed into a 2v manifold. As long as you have good gasket seal and no vacuum leaks, you should be just fine useing your Motorcraft 2v. The downside to the Motorcraft is that getting different jet sizes for it if it's needs rejetting is getting tough. You can always easily upgrade to a Holley 4V or Edelbrock/Carter 4V square bore later, if you wish.

BBT

 

The only problem with running all those vacuum lines into one is that the port those all go into feeds only one cylinder. I had my Edelbrock intake hooked up like this, and it caused that cylinder to run leaner than the others. If Edelbrock would have cast this port just below where the carb mounts, it would be much more versatle; otherwise, this port cast on the #4 runner is only good for static vacuum applications such as auto tranny modulator and probably the brake booster, not PCV which has a constant flow through. Most new afermarket carbs have a large vacuum port in the rear that will handle most everything. What is the possibility of drill & tapping your adapter/spacer for a vacuum port?

 

that's some interesting info that i did not think of.

however, what's the difference between 'static' vacuum and what pcv valve needs? I know the small vacuum on the carb is usually 'timed', but i assumed that everything else was constant vacuum. are you referring to the fact that because it is on a cylinder port it would only be vacuum on the down stroke? is that not good enough for pcv?

as far as drilling the spacer, i'm not going to go there with my inept mechanical abilities. if you can convince me that having the one vacuum would not be suficient for correct pcv flow, i would dish out for another carb which will also have the additional intake.

 

What I meant by static vacuum (it is probably not the right term) is the devices that do not have a constant flow of air refreshing the vacuum line such as tranny modulator or the brake booster that are pulling against a sealed diaphram. A PCV system on the other hand is always sucking fresh air from one side of the engine to the other in order to vent out all of the blowby gases and burn them. If only the #4 cylinder is recieving the PCV flow, then it is possible that it could run a little too lean or too rich depending upon the amount of blowby the engine has. With it evenly dispersed between all 8 cylinders, the effect won't be as dramatic, and any change in air:fuel ratio the PCV causes can be adjusted at the carb for all cylinders. Give it a try and check out how the 2BBL adapter works, just keep an eye on the #4 plug, it is possible you will have no problems at all.

I was very disappointed in the mileage I got when I put on a new Carter AFB to match my new Performer manifold. It dropped from almost 13 to no more than 10 MPG. I installed leaner metering rods which brought it up a little to about 11.5 MPG, but at that point, the power was not much better than the old Autolite 2BBL. So I made an adapter plate out of 3/8 steel plate and tried the old 2BBL again and mileage was back to 13. Unfortunately, I promised to trade the old Autolite to a friend when I got my 4BBL setup completed. That all took place back when gas was less than a buck per gallon; sure miss that old Autolite now.

 

thanks, i understand better what you are saying. i'll keep an eye on the #4 plug and might give it a shot at drilling the adapter.

 

Couldnt you use the spacer that has the water passages and vacuum ports in between the carb and the adapter. Just a thought.

1979 F150 CUSTOM 2WD 302 BORED .040 OVER EDELBROCK CAM, CARB AND INTAKE. C4 TRANNY AND A 9 INCH REAR END

 

you'd have to put in on top of the adaptor to get it to fit onto the 4bbl hole in the edelbrock;

of course, if I cut out the hood and had the air filter sticking out like a hot rod i could do that...<grin>...but then I would have to paint it black and get mag tires...

just kidding; thanks for the suggestion.

let's end this thread. the carb's on there and sitting pretty. i forsee getting a 4bbl with extra vacuum intakes in about 6mo to a year.

I just can't get her to start. I posted my electrical problems under "no start after new intake". Appreciate if y'all took a look.

thanks for all the advice and warnings about the adaptor and vacuum! it was a big help and i learned a lot as usual.

 

The only problem he might have is hood clearence to the air cleaner. The Edelbrock manifold is taller than the stock 2BBL cast iron plus the addition of two spacers; he is probably looking at 2½-3 inches taller than stock. It would be wise to put a ball of clay on top of the air cleaner and slowly lower the hood to squish the clay. If the clay is at least 1/2 inch thick at the tightest spot, I would say he has addequate clearence for engine/frame flex.

With the 3/8 in thick steel adapter I made as the only spacer between the Edelbrock manifold and Autolite 2BBL, I could not get the hot air intake from exhaust manifold to mate with the air cleaner due to the additional height of the Edelbrock. When using an Edelbrock intake, height will be close to stock when no spacer is used.