Carb/Gas/Tranny issues

none67

New Member
Oct 19, 2003
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Hey, as some of you know my plan for my 289 is to use a 2x4 (i guess about two 400cfm holleys). My questions are:

I plan to use a Toploader 4spd, now with dual carbs we all know the gas issues involved. I need to get atleast enough gas milage to drive on the highway a lot, and i here you can buy these OD gears that attaches to the end of the tranny so that when your on the highway you can just click a button and it will take over. Has anyone else heard of this?

Also, if anyone has any experiance with dual carbs I would like to know if its alright to use on the streets (I know its not hte most practical thing in the world, but..) without stalling all the time, and bogging.. i hate bog.
and is it possible to set up the carbs so that the second one only opens up at about 3/4 thottle, that way I don't really have to burn a lot of gas till i need it.

Thanks
 
What ur talking about is a gear vendor. I want one too. Only one problem for you though....I'm pretty sure they only make them for autos. You have to run the two carbs with the same timing. Other wise you will confuse your carbs. This is how you have your cake and eat it too. You jet you carb as lean as it wil go with out stumbling. Then you modify your pvcr in your metering block and whamo!!! You have a ten second car that gets 15 + mph
 
2k+.. woa, thats waaaay over my limit right now. (for a single thing like that i mean)

how do you mean fustrated with them? please explain. I'm 16, and i looove my car so i make plenty of time for her :).


10sec, man say again? soundsa bit to good to be true. 15+mpg and two carbs running at the same time with good proformance. can you explain what you mean by "modifying"?

thanks guys, really helps
 
You take ur car to the track. richen ur car up and up and up till ur MPH drops off. Remeber those jets. Then you put the jets I was talking about. That's what gets you ur good mpg.it'll be running lean. After a lengthy equation of pie times this and dive by this and that you get a number..(more on that later)You power valve lets in the extra gas you need when you floor it. It has it's own jets(power valve restrictios channel(pvcr)). If you know the magic number...you open the pvcr up to equal the same jetting that you had at the track so you aren't actually running lean when you jump on it. This my friends is how you have ur cake and eat it, TOO !!! When I get my speedo corected and take it to the track and figure all this out for my car, I hope to have a 10 sec street car that gets 18-22 MPG. I know a guy that has a 455 pontiac that gets 19mpg with a 850 double pumper. WOW !!! eh ? :worship:
 
The power valve does not have it's own set of jets. Period. There are only two jets in a Holley 450 cfm carb. These are the primary jets. The secondaries have metering plates. A better choice for 2--4 bbls on a 289 would be two 390 cfm carbs. I ran 2--4 bbls on a 427 back in the 80's and it would get 20 mpg with them , as long as you kept your foot out of them. The front carb was jetted two sizes richer than the rear, to compensate for the fact that the carbs are offset to the rear on a 427 intake. This also is the case on the Ford 2X4 intake that mounted two Holleys. Tuning wasn't as hard as you have been told. And once tuned, they tend to stay that way just as on a single four. Throttle response was also terrific, with both carbs in sync with each other.
 
hey thanks a lot D, i think thats what i will do. 390s sound good, and the 20mpg sounds better, because if i floor it then it will be for a reason that i don't really care about the money. can you suggest a good intake?
 
I would suggest you consider a 5-speed. The 5th gear is an overdrive, which helps on mileage. The first 4 gears are about the same as your 4-speed. (That's what I did on my '65, and it's a VERY easy swap. The shift lever even comes through the floor in the same place!!)
 
well i was thinking of a 5speed.. but it doesn't have the same oldschool/manly feel to it as a 4speed. i mean nothing wrong with them. but saying "yea, its got a 4spd" sounds better than "yea, its got a 5spd"
 
mustangkid5 said:
everyone I know that had a two carb setup got soo fusstrated with I took it off and put a single carb intake on it and neverlooked back.

You don't know me.....but I agree ;)

Took of my tunnel ram with tqin 600 q-jets...and the end results after alot of other stuff was a MUCH faster car
 
none67 said:
well i was thinking of a 5speed.. but it doesn't have the same oldschool/manly feel to it as a 4speed. i mean nothing wrong with them. but saying "yea, its got a 4spd" sounds better than "yea, its got a 5spd"

Actually I get goosebumps when I look at a nice old stang and the owner says... 'Its got a 6 speed"
 
See now. dang it hearne you didn't read close enough. And a pv does have does have it's own "jetting". Period. Jets are the lamens terms I used. That's why the () with the pvcr was typed in them. If you open them up, it will run richer under a higher load. They are not removable, so you better get that junk right the first time.
 
No, I did get it right, you said they had Jets. And as far as the PVCR, that sounds like a load of BS to me, I've been fooling with Holley carbs for 30 years and never have I heard that term used for any part of a Holley carb. I read your post two or three times and still was baffled by what you were referring to. And it's LAY MAN'S terms not lamens, so maybe you need to "get it right" the first time.
 
like i said, i got nothing against 5 or 6 speeds, but i don't think that it suits my car is all.. if you were making a modern car, then ya its cool. i dunno could be just me.

oh and dodgestang, i was looking at your car on your page, and it says for june/july you ordered a hood scoop. that is the type of scoop i was looking in to buying. is there a reason why you didn't keep it? thanks.
 
none67 said:
hey thanks a lot D, i think thats what i will do. 390s sound good, and the 20mpg sounds better, because if i floor it then it will be for a reason that i don't really care about the money. can you suggest a good intake?
The only intake I'm aware of that will allow you to run two Holleys ( aside from a tunnel ram) is the over the counter ( circa mid to late 60's) Ford 2x4 intake. I see them on ebay frequently, and Mustangs Unlimited sells them new. This is NOT the same intake Edelbrock or Offenhauser lists. With these two , you cannot run two Holley's in line, the spacing from pad to pad, is too close. I have thought about using the Edelbrock or Offy intake with two Holley 2 bbls on adapters though. :D
 
The power valve circuit does not have jets, but it does have an orifice that can be enlarged. By drilling it out you can run smaller primary jets and your mpg will increase. Most of the blow thru guys (turbo) are doing this to help drivability, but can help anyone that wants more mpg. This mod is not for the novice tuner though. Drill too big and it is hard to put the metal back.
 
Oh yeah, 2 carbs are not twice as hard to tune. They are 10 times as hard to tune. There is a cool factor involved for the average street person, but most people that have been around cars much know that unless it is a prostock type motor, you are shooting yourself in the foot. If you are going for the look, you'll be fine, but there are better setups for any car short of a max effort engine.
 
D.Hearne said:
No, I did get it right, you said they had Jets. And as far as the PVCR, that sounds like a load of BS to me, I've been fooling with Holley carbs for 30 years and never have I heard that term used for any part of a Holley carb. I read your post two or three times and still was baffled by what you were referring to. And it's LAY MAN'S terms not lamens, so maybe you need to "get it right" the first time.[/QUOTE

Wow good for you. You can spell lay mans correctly. PVCR is not a "part" it's what allows the amount of fuel through th PV just like a jet. Damn I'd feel pretty stupid working on Holleys that long and did'nt know what a PVCR was. I haven't even had a holley 3 months yet and know what it is. Maybe you need to lay the dictionary down and stop worry about words no one cares about and pic up a good holley book and would probably read it wasn't as much BS as you think.