Technical What carb for tunnel ram

I set up a tunnel ram with dual 450 Holleys on a very stout 383 stroker. After timing and jetting, this thing just flat out runs! Two pumps and it starts cold, and idles with no choke. Does not load up, stink, stumble, falter, hiccup, or stall. The car has a Muncie 4 speed, 3.50 gears, and gets 14-16 mpg. I know what your thinking.....B.S. I would not believe it if I heard it either. You can lug the motor down to 2000 rpm in hi gear and just stuff the throttle. Accelerates clean, no jerk, and about 3800 rpm, well, that's when it changes into an animal. It can be done with 450's. Would I do it again, you bet! Drivability is outstanding. Been this way for 3 plus years.

 

^ It can be done... I know, after all, i've built dozens for people that could not figure it out themselves,-n- so does mrhp-n- plenty of others.

 

I Disagree!!! I drive my on the street ,in the winter I go two jet sizes richer. Temp 20-30's in winter , It's all in how much effort you want to put into turning yr engine & the carbs correctly.
My jalopy /HR is not one of those car that will not run ,I play on street!
I get a big kick when a HellCat ,ZO6 ,one of those 700 Hp Sheby try me in 1/8 & I cap there A$$. This is on street or track, I whet to local track ,they let me make a pass , they see 2 two barrel carbs on tunnel ram ,(2x550s). stock 283 vale covers dings & dents, stock looking fuel pump with hard lies to carbs , 32 gastank ,Stock looking fan , BS block hugers threw full exhaust, 7 inch Bridgestone tires , Made One pass ,was told I would not be able to make another pass untill I install seat belts (stock model A bucket seats) Slow it down Or add a Cage ,
My car is not all blinged out, it just has a set of ET on rear Mickey pro 5s on front .

 

So I'm supposed to listen to what's posted,well so far I've been told to run vacuum secondaries,double pumpers,650 and under or at least 750.... Jesus. And IM the crazy one?

Looks like a vacuum secondary may not even fit with my radiator rods and I don't really want to bend them up.

Also as stated it's a weiand ram,.ive heard they are around 2400 rpm and up and are one of the more streetable rams. Currently my cruising rpm is around 2200-2500rpm. So to me it sounds like I'd be in about the right spot.as stated it's got a 3k stall,headers,accel mechanical distributor. I've had a 650 edelbrock(I hate them but it's what I had) and a holley dominator single plane in it before. I car literally felt like nothing changed (previously stock intake with a 500cfm. So to me that indicates that this shouldn't be 'totally not do-able,forget it negative this that no way'

Anyone here actually done it?

 

I just said what carb I would use if I was going get that bad boy tuned up.

 

Go to AFB,s and they have mechanical secondaries and no power valve to screw up.

 

Saltflat-Yeah,about the only one haha

But why so big? I called holley,there got s 650dp on special for just under 370$ I think. They advised me it's still too large for what I'm doing. I really can't fit a vacuum secondary nor do I really think those are going to be as good on an intake with weaker vacuum signal.


Chris- isn't an afb just like a edelbrock? I know I've had both afb and edelbrock and hated them. (On my single plane intake,they could never handle sitting for a month without needing a rebuild) Also as listed I'm only using a single carb.. and a eddy-afb is too wide to clear my radiator rods

 

Your setup is nearly identical to mine ....with the same results , mines been "just fine " for 8 years , overall mpg = 16.5....

 

My thought on this is there is a large volume in the intake that has to filled with an A/F mixture and a larger carb will fill it better than a small one.
And a 750 should be something that can be tuned to your needs.
This is just what I would do other would not.
I am not like others.

 

Some of you guys are in left field and I wonder if you even ran a tunnel ram or took the effort to make it run right.
As far as the original poster goes it seems you're stuck on 2400 rpm and want a out of the box magical carpet carburetor ride.
You can Google tunnel ram dyno test and it'll show that tunnel rams increase torque and hp as low as 3000 rpm over a single four intake. These tests are done on chevys, Mopar and fords. That being said don't worry about the 2400 rpm !
Now as far as 450's don't work, that's a crock of shit too, tune them and they work damn good and by tuning I don't mean just screw the mixture screws. Your hate of Eldebrock carbs show you may be lacking in the "tuning department ", don't take that the wrong way but just saying with effort practically any carb can work.
Now to get down to the meat and potatoes the 750 double pumper mechanical secondary that was recommended, yet you balked at, is a great carb to start with. It will provide the fuel to fill those big runners but will need tuned to work perfectly. If you don't want to put forth the effort then don't waste your time with a tunnel ram.

 

I like how threads eventually get filled with so much missinfo that new posters start assuming.

I built this car out of a few rotted panels. It wasn't even a whole body. Why on earth would I give up on the car now?

I've called around, everyone so far has told me 600 or under cfm. While I think 650 sounds better.ive been told a 600 vacuum secondary holley will be great,and also been told a 600 double pump. I'd assume a 650 double pump would work well because of the secondary squirted should help with lean bog and be more tunable.

I still am not sure where to go but as mentioned I really want to hear from folks that have ran T rams. I have heard before that a tunnel ram CAN run bigger cfm than if it was running a smaller intake.

 

Just thought about this,let me ask- you say more cfm will be better, I'm assuming now that the reasoning is-

A big intake is letting the engine pull more at all times therefore you have to fill the need?

Most that say go smaller say that it's cause the intake is so large it needs to be choked down so to speak,that it's so much intake that I need a small carb to keep its torque up

 

If the "new poster" comment was for me all I know is that I have 3 cars in the garage with 2x4 intakes, 2 are Holleys and one is Carters. They all work great street or strip, cold or hot but none of them are right out of the box.
It also sounds like you want to take the advice from a call around desk jockey rather than guys actually running and dealing with it first hand. Why bother asking for advice here if you dont want to hear it ???

 

I have run several tunnel rams over the years. Ran 450s, two eddy 500s, and 2 750DPs. Had to put in a certain amount of tuning and testing on every set up. If you see a deal on a 650 DP, or 750 DP , try it. But be prepared to TEST AND TUNE. Any of the carbs I mentioned can be made to work, but it will take WORK.

 

Swade- it does now. Because you again are assuming who's advice I'm taking. I told you I had been advised to go both ways. So then how exactly am I deciding one or the other you or them? Is a 750 dp really that much more important? My main question was vacuum or mechanical.

I asked a question on why the cfm needs... still waiting on that

 

Are you putting this tunnel ram and single carb on the Model "A" in place of the three deuce set up or is it for another car?

 

Yes,I'm taking my 3x2 off. I am not selling them. I'm just taking them off to go through them and get new bases and such,then the tunnel ram may go on my 383.

Bottom line,I'm wanting a change,and my 3x2 keeps leaking. So I'm going to try this for a while. I plan on keeping my 3x2 and maybe even trying to adapt them to a tunnel ram in the future.currently I'm am just fed up with them leaking and need the car up and running without the carbs leaking all over.its a hotrod,I like changing things once in a while for fun.

 

I think you need to go.your first post isn't even English. Never used the 'ignore' button before,till now


Anyways,any other folks that have ran t rams are welcome to talk about your preferences

 

Hooligan,
I can't say for sure, but I will just about bet that the intake is going to want a carb in the 700 cfm range. Double pumpers are usually for motors with a lot of overlap on the cam and a very low vac signal. But the double squirter may work well with your set up too.

You know that I am a holley guy by nature, but something that you may consider is a Carter Competition (a souped up AFB), they come in the 700-725 CFM range and are usually not too pricey used.

 

Good ol porkbeaner,the staple of the hamb. The fellow that always has something constructive and useful to say and has been there since I first started and has never sent me wrong or added any b.s

Well,I don't want to buy used,I keep finding junk I guess. 2 edelbrocks and 1 afb comp series later they all have been taken off at some point from my car back before my 3x2 days. I deff am leaning towards a double pump because I really can't fit anything besides that in between the radiator rods and I like the look.650 is really too small huh?

I'm running a comp dual pattern 268xe cam I believe

 

Well fule injetion is maybe a way to go if you do not what to try diffrect Carbs ,
I have over 40 different carbs from 2 barrels to dominators .
Maybe 6:60s @ 103 in 1/8 is not fast for a street pass, All my tunnig was down with Common Tunning tools , knowledge & LOST'S of notes , trial and error !!
I know of a lot of guys just can not get there Ride to run correctly even for a Hight 8 1/8 th
Pass ... Maybe they just do not know how it should run or when things are correct.
I know my set up is not FULLY correct ,If i was to tune on wheel dyno there more in it ,
But I Know I have put the effort into , it shows & perform's

 

I'm not willing to try carbs? Are you going to buy them for me!? I don't have the money to buy and try different kinds of carbs. I'm with ya on the trial and error,I agree with ya.but my pocket book isn't so much on that same page.


Anyways I think I'm going to try injection. I've already bought the spray bottle for the fuel,next part I'm getting a little monkey to ride on the cowl and spray the intake.

 

The 650 may work for you just because you are probably opening the secondaries sooner than most 4 bbls. The key is to keep the plenum full of air and jet accordingly.

Do you have a model number for the weiand? We can probably go to the Holley site and find a suggested CFM for the intake. The joke on that is that a lot of performance rated Holley/Weiand intakes are rated for 700 CFM. Do you know how hard it is to find a 700 CFM Holley carb?

 

I guess when you are looking at it from the other side of the fence it's easy to tell who is steering you right and who isnt.
All I can say again, is what ever you choose you have to work at it to get it right. Maybe I'm wrong but by your comments of how you removed 2 Edelbrocks and 1 afb, along with I'm tired of my 3 deuce leaking so I'm changing intakes kinda says willing to work out the problem isn't something you want to do.
Good luck with whatever you decide.

 

Porknbeaner-I hear ya,haha and it's impossible

Swade,cool I can see you are alright. Well my 3x2 has been built and 2 years still isn't right. It runs okay but still leaks and I can't seem to get my fuel pressure down enough. I actually plan on getting them fixed up,buying onther tunnel ram top and make a 3x2 tunnel ram. Not sure if it would work but I'd like to try it when I can afford to. Then this carb will go on to my 383 4spd 3.73 geared pickup

The comments on the other carbs is,they really wasn't worth messing with. They was old worn out carbs that just never seemed to respond to anything I did.i wasn't a fan of spending on those afb styles,they just look fugly to me so there was no drive to keep spending money in any of them.they really probably was just junk to start with.

All I can really say is I've had some of those summit autolite/holley hybrids and they ran great on my off topic 67 302's.

 

That's why I said 750

 

You did,no one is saying you are wrong at all,nor swade either.

 

Porknbeaner,I've just got that standard weiand tunnel ram. 3984 I think it is.

All I can find is cfm calculator that doesn't account for a tunnel ram and cam.

Just the generic calculators say 630cfm for racing application and around 500 for cruising

 

If it is any consolation I had a Q jet on a truck in Mexico that I absolutely could not repair. I did one of everything to it and I no doubt could have repaired it if I could have got the rind off of it. Made a good paperweight though.

great minds. . .

 

I would look for a carb with the down leg booster as to the straight leg.
I have had better luck tuning them and seem to be more street friendly.