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I ran a holley pro dominator tunnel ram with 2 660 center squirters. I did drive the car on the street occasionally. I didn't run power valves so it would run alittle rough right off the idle circuit and clean up and run great! It did use up alittle more fuel than a single carb. Also the fan goofed up the airflow so I had to put 2 inch spacers under each carb and I also had a foreward facing scoop.

you could use a edelbrock or weiand tunnel ram thats taller and use 2 450 carbs and should be fine. The carbs have vac secondaires.
 

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We are venturing into that territory here real soon. Got our tunnel ram at the powder coater right now. We are going to run 2 4160 450's mechanical secondary's.


 

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Discussion Starter #4
I was thinking the 450's also, but my carb guy at ProSystems hates 'em. Believe it or not, he actually suggested the Edelbrock 500's. I was surprised. I need something that will idle, start, and run happy between 2000 and 3500 rpm (plan to drive this heap on Power Tour).

Also, I didnt know the Holley 450's were available with a mechanical secondary. This would probably work well with my stick shift.

Thanks so far for the responses.
 

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450's

eh ,, the 450's have mechanical secondarys but they're not double pumpers or center squirters. They're used to be a kit available back in the day , to add a squirter that had an extension that had additional tubes that would feed pump shot to the secondaries. Problem is , it does this all the time , not just when the secondaries are being pulled in.

You can find 600 vs holleys dirt cheap on ebay that would prolly work pretty good too ,, or i saw 2 500 2 barrels do pretty good on a 327 a friend had.
 

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i have ran almost every thing on t-rams ! the 450 mechanical carbs are THE WORST ! they produce a massive lean bog when you punch it ! BECAUSE OF LACK OF PUMP SHOT ,AS STATED ABOVE ! .. THE holley 1850 is the easiest carb to run .. BUT it usually is a bit much for your basic streetrod . The holley 4412 2 barrel is a good choice ! but i would remove the 50cc pumps on them .
AS for the edelbrocks , IM a HOLLEY guy , sorry no help there !

Now if YOU CAN FIND the old holley 450 with VACUUM SECONDARIES you have found a perfect streetrod carb .. Search ebay , they come up every once in a while .
 

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I guess we will find out how these 450's do. I personally seen them run on a built 327 and the car ran like a raped ape.
 

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The best streetable carb for a tunnel ram is a Holley 390cfm carb 0-8007

These are vacuum secondary carbs. they are in 99% of the time just bolt on and go!

IMO
Al
 

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The best streetable carb for a tunnel ram is a Holley 390cfm carb 0-8007

These are vacuum secondary carbs. they are in 99% of the time just bolt on and go!

IMO
Al
Al,
What's the actual difference between the 450 and 390 CFM carbs? (venturi and butterfly size).

Just curious because less than 800 CFM on a tunnel ram does seem kinda small.

Why not just get the 600 VS carbs and go from there? They're a dime-a-dozen.
 

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I am currently running 2 750 double pumpers on a edelbrock street tunnel ram, on a 496, aluminum heads, big roller cam, and 11.5-1 compression. with e-85. If the carbs weren't sticking through the hood you would never think it was a tunnel ram and 2 750's.
 

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Discussion Starter #12
Really? So, whether it's the 390 or 450, go with the vacuum secondaries? I generally naturally go with the mechanical for a stick shift, but if you've driven on the street with 'em, then I guess that's the case.

Why can't the lean bog of the mechanical be resolved with a bigger pump shot?

Thanks again,
 

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I ran a set of 660's on my 385 with the Weiand tunnel ram. Never had any problems. For a stick shift car i would go with a pair of 600 dp or the 660's unless its just a cruiser and dont really care for max hp. We've had trouble getting a vacuum secondary carb to get a good enough signal to pull the secondaries open on a tall tunnel ram. We didnt believe it till we did the test. It was on a decent built 355sbc.
 

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clutch

the 450's might not be too bad if you maybe hook up a 2 step to the clutch pedal , for full throttle launches. That might help the engine deal with the lean spot. If you drive it and just ease into it while cruising knowing and expecting the stumble it will experience for a second. The ones i had used alot of fuel was my main complaint about them. Got a sweet deal on 'em. Looking back maybe i should have tried a few more things with them before i took the tunnel ram off. It really did run alot better than with a 650 dp though.
 

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My Dad helped me buy a tunnel ram in 1970. It looked like a tissue dispenser sitting on old furniture legs. Only thing it was good for was blowing the gasket where the box bolted together. It was new, then.
 

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how about 2 holley projection throttle bodies.have the cool look and tbi control them with megasquirt though 100% tunable
 

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I've got dual 450s sideways on a weiand ram 406 sbc. I converted them to 4 corner idle to get the plugs to even out their idle color. When the carbs were inline they still had uneven plug colors (sec side was rich), the pattern was just 3478 rich instead of 1357. The motor ran the same either way. I've also converted them to vac sec to slow down the initial opening and get a crisper launch. I probably should have got the 600s (Summit combo) but when I ordered it I thought the 450s were vac sec. All the bosses are there, you just have to finish drilling and tapping them. I robbed the secondary shafts and diaphragms from a pair of 3310s. They work good now but it took a lot. Lucky I enjoy tinkering!
 

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did u ,,

I've got dual 450s sideways on a weiand ram 406 sbc. I converted them to 4 corner idle to get the plugs to even out their idle color. When the carbs were inline they still had uneven plug colors (sec side was rich), the pattern was just 3478 rich instead of 1357. The motor ran the same either way. I've also converted them to vac sec to slow down the initial opening and get a crisper launch. I probably should have got the 600s (Summit combo) but when I ordered it I thought the 450s were vac sec. All the bosses are there, you just have to finish drilling and tapping them. I robbed the secondary shafts and diaphragms from a pair of 3310s. They work good now but it took a lot. Lucky I enjoy tinkering!
Did you block the constant feed discharge hole that feeds from the transfer slot and drill the air bleeds to the same as the primary bleeds when you made it into a 4 corner idle ?? That might have caused the secondary to be rich if u didn't. Really cool you made them into vacume carbs.
 

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Yes I blocked the constant feed holes. They were the reason the mixture was so rich. I drilled new holes to intersect the idle fuel from the mixture screws (copy of primary side). Also blocked the transfer slot in the throttle body to isolate the secondary side. I used primary blocks from a pair of 3310s on the sec side. Tapped the ifr, air bleeds, and transfer slot feed to use brass set screws drilled to size. Currently the ifr's are .022. The vac sec conversion changed everything with these carbs. I was ready to toss them before. Large shooters and 50cc pumps got rid of the bog but killed the part throttle response. Now I use .025 shooters, 30cc pumps with pink cams and I'm going to try smaller ones. The 450s can work but I don't know why Holley made them mech sec with no pump.
 

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Flashback. For fun I gotta tell you about the center squirter carbs Holley came up with for the tunnel ram back in the day. The 1:1 linkage was hell, all throttle open.
 
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