Technical What carb for tunnel ram

Just edited my previous post. Calc says 630 cfm but not accounting for a t ram,cam or anything

 

Yep! I have heard of that and believe you to be right

 

This is what I was planning on but am on the fence since you fellas are saying it may be small

 

Have you called Quick Fuel and ask them about what you need?
I would like to know. I'm just and old hayseed that got blown over one state.

 

No,I've only called holley,summit and some carb shop in ny that I heard is supposed to be good but they told me 600 vac secondaries so I think they are not right.

 

Just tried. Number says it's holley

I called holley back,just to see if someone may have another opinion. They said they still recommend a 600 to keep the air velocity up

 

I just fond out that Holley bought Quick Fuel.

 

Yeah,they don't even offer a 600dp in the price range that the 650 is.nor anything north of 650cfm unless I go to vacuum secondary

 

https://www.summitracing.com/parts/qft-sq-750
Not in your price point but this with a shear plate and a few jet changes....You would be happier than a punk in boys town.
A little shopping you may find a better price.
I have been carb shopping and looked at some Holley's and have found that picture they show is not the carb they are selling so make sure you read all the fine print.

 

Yeah that's a little bit steep for me right now.

Holley had told me since I'm under 6k rpm is why they recommended what they did.

 

I am not saying it wont run with the 650 and you may be just fine with it.
The theory is that your A/F ratio need to be correct no mater what carb goes on it.
The only thought about a rebuilt carb from them I would take as someone tried it and it didn't work because....well who knows...maybe the wrong size or just something wrong with the carb itself and the kit didn't fix it.

 

I agree with you 100% on all of that

 

I would make sure you get connected with somebody local with very solid carb tuning skills before you even consider swapping out the current setup.
As James and Phil have said,these things will need a bunch of finessing to get bogs,stumbles,flat spots,etc out of the way it runs,but if you have a guy that can sort of help walk you through it,it won't be so bad.
I would definitely stick to the bigger (750cfm) carb though,as James indicated.
I don't know exactly why these intakes behave so differently from a single carb single or dual plane intake (probably,like James said,giant plenum to fill),but they do.And they want to be fed lots.

As for the Holley tech guy on the phone: They're going to tell you some generic formulated answer every time you call,because they sell approximately zero tunnel Rams these days,the guy on the phone has probably never run one,and they push hi rise single plane stuff for performance applications nowadays.

If you have to run a single carb,run something bigger than a 650cfm.You'll be glad you did.
I would personally run two carbs,but if budget dictates one,try to make the best of it with a bigger one.I would be tempt to go even bigger,but you should be able to find a real nice 750cfm Holley that's been tuned up real nice on Craig's list from a racer...Those guys are constantly switching out really high quality parts because they upgraded to a bigger/faster combo that now needs a 1050cfm carb instead of a 650cfm carb....You may end up scoring $1000 worth of carb for $300-400 bucks,which is less than a lot of box-stock Holleys.

Don't forget about that ignition stuff I mentioned earlier,too.A stock distributor will be a headache when trying to get this combo to work right.

Scott


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I mentioned already I do not have a stock distributor.

Yeah I agree with the thought of holley probably just forms up some number not really taking into account it's a T ram and just push for what has worked for most others.

 

I have found one of those vintage speed carb adapters to put 3 2's on a 4bbr intake. Was sorta thinking about making a 3x2 tunnel ram with it

 

I thought the whole reason you were switching to a tunnel ram was because your 3 2's were leaking like crazy,and you wanted to get rid of them?


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It is hahaha. I will be making the 3 2's better while I drive the car off a 4barrel.going to get the bases fixed and all that.then throw the 4 barrel on my other motor that's in need of a carb also.i never want to get rid of the 3x2 I just don't want to drive them how they are and want a change for a bit

I also like grabbing aluminum for some reason. It's used and cheap so I figure why not at least grab it.

 

If you can get your hands on a Predator carburetor might work best for you,
I do have one .
Tri power , that another discussion , I talked to the gentleman that develop the try power for GM some years ago , try power only works on the engines they were developed and engineered for ,most here will say there tri power runs correct but they Do Not they were special built carburetors for tri-power set up's , Even carburetors 2,4,6,8 work better then odd number carburetors ,
But most will disagree less you've actually experimented with these set ups

 

I've had tri power for years. And they have been set up for this engine.

I agree,I'd think even numbers would be a bit better.

I know basically nothing about predators other than they look like a box. I'm willing to listen tho!

 

Looked them up,they are a bit pricey. The whole 390-900something cfm is interesting. They look very simple. Not sure where to find one of those round these parts

 

I'm not here to bash , But if you want a 95 % trouble free ride you will have to work on it lean it an experiment , or you will pay to have it done , & there will be times you send the $$ & still be incorrect ,I don't know everything but I'm willing to put effort into , I have a stockpile of parts because I've been doing this crap since the age of 10 , Now 40's
The engine in my jalopy , dude it's maintenance , vavle springs evey 3-4 mouths ,Change pluge's with oil change , Roller lifter's Crower Endura Max once a year really you're supposed to change them every 2000 miles or like 250 1/4 mile passes , but I taken a chance , all 16 vavle Titanium, its now to the point I change complete Engine every 12 mouth, next engine going in is new Combo ,I will have to see what it takes to tune , So a different set of carbs , this one I think will need more CFM's I am thicking 200 more ,, this one will make about 175 hp more ,car might slow down by over powering , might have to go to a Glide , I refuse to put Slicks on .Race Egine on street its hard on parts , but I drive all most daily , But its not like the Rush going over 200 in 1/4

Op just think about what you want,read up experiment , HotRod's !!! you can get over your head fast , Carburetors are expensive , especially when you're on a budget , We all have been there to only buy one time , but with modified engines it's usually not the case ! Maybe some one in your Area is here on the HAMB has a set of carbs you can borrow , To see whatever CFM's they have will work & function close to correct, I use a Race cfm Calculator , it's more detailed . More information is required .

 

Uhm..

 

You do realize what day it is?

 

Not untill just know,
But I am not Fooling
2:30 am here , doing 16 vavle seal change

 

I would run a 750 Holley double pumpers with a big squirter like a #35. Four corner idle is good but not necessary with a plenum tunnelram. As for the myth that tunnel rams are for high RPM only is false. If you have two big carbs then power will come in a bit later but cam and heads and exhaust all have an effect and the carbs or intake always gets blamed for poor performance.. The truth is long port runners are for huge boost in MID RANGE TORQUE not high RPM! Short runners are for high RPM power!
Use a vacuum gage to help you with choose the right powervalve and that info is easy to find on a google search...Everyone is so scared of Ram intakes and really when set up and calibrated right THEY RULE!! Enjoy..


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Also use the #2 pump cam position on the secondaries to delay the pump shot around town.


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Quicksilver- thanks for the advise. I did make a deal with a carb guy around here,I had a floated coded carb that we made a deal to trade for him building me a 600dp. He said he ran one on a single ram and really liked it.

 

Any updates?Got your carb back?


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Sadly no. The guy that was supposed to be building a carb for me flaked out on me.

I've got a 650 quick fuel double pump that just may be going on it for now since the other carb fell through but I doubt it. I'll probably be waiting and looking for a carb still

 

Center squirter


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