Last time. The more people you ask about carb size on a tunnel ram the more different answers you get. Im pulling the trigger on the carbs this week. Getting the Holley ultra xp carbs. Talked to Mark Whitener and he suggests 750's. I always take Marks word for anything about carburators, but 750's seem to big. Called Holley and they suggest 600's. i'm thinking 650's.
Holley pro dominator t ram on 410ci sb 13.3:1 with a 7-7500rpm ceiling. 5200 stall and 3300# race weight. i'm more concerned about not over carbing between 5200 and 7500 since that will be the usable range. Thanks

do yourself a favor and take Mark's advice

I ran a pair of 750 double pumpers on a 383 B motor, and once dialed in were deadly accurate. Tunnel rams breathe different than a single 4 intake, and the rpm you are looking to run you will be fine.

I don't know [ Moparts Family Site - Keep it Friendly ] Holley is thinking but I'd be worried the 750's are TOO SMALL. I have a great amout of respect for Mark so I'd have a hard time questioning him either. But at that displacement and RPM the 750's are borderline too small for me.

FWIW I'm making the GIANT ASSumption that when you ordered the cam you specifically bought a cam spec'd for a TR. There are 2 GIANT issues that kill TR's and it ain't over carburation. It's way too much timing. TR's can use 8-10 degress LESS at .050 and run the same RPM. DO NOT OVERCAM A TR.

The second issue is getting the air bleeds and emulsion sorted out. You are doubling the jet area, doubling the bleed area and doubling the emulsion but you did not double the air flow.

If you do those 2 things you will wonder why you did run TR's forever. They make more bottom end, have a flatter TQ curve and make more average HP every single time it is done correctly.

In 1984 I bought my first TR. I personally spent hours on the phone with Ollie Morris (IIRC that was his last name...I'm horrible with names) and he had his own formula to figure out TR carb capacity. He also taught me how to think of airflow in term I can understand. Ollie was an awesome man. His answer was always very simple. If you had a properly sized single 4, and all the dyno numbers looked like they should, then you DOUBLE the CFM rating for a TR. I don't remember the last time I talked to him, but he stood by that every time I questioned him. That always meant that you had enough converter (I run clutches so I never had to worry about a tight converter) the CORRECT gearing and the chassis was sorted out. If you consider that, then you could really find HP in 2 1050's.

Now all the math heads can come in with their formulas and calculations and theories, but they would still be wrong. How do I know? Because in 2015 all the Pro Stock guys would have been stupid. By any math I have ever seen, they are grossly over carburated.

All I can say is I am doing a new engine for my DD/street car and it's the first time I'm not using a TR. I don't want to cut the car up or change it any more than it already is. Otherwise, I would have a fully ported and flowed TR on it, and I'd be running 2 850's. On the street. And Thumprdart would do the carbs.

You should select a pair of carbs. that flow the exact same amount of CFM through both ends of the carbs. Holley 750 DP do, so do 850 D.P. and most Holley 1050 Dominators. The Holley 650 D.P. have different venturi boosters in the rear than in the front, I'm not sure about the 600 D.P.
If I was you and know what I know I wouldn't hesitate a second to buy the Holley 750 D.P. tunnel ram carbs IHTHs

the cam is 267/275@50 .675/.675 on 106. I think the cam may be on the small side for what i'm doing. thanks for that info on t ram and cam size. I am most concerned with going fast in the upper range, but may drive to a car show or two. Do you think it would be drivable enough for that with 750's? maybe 10 mile radius.

well, the holley doen't offer t ram carbs in the ultra xp line, but i'm sure Mark can suggest what they need for IFR, emultion and main jets. looks like 750's may be best.

Absolutely. If you get the issues noted above sorted out, you'll wish all your stuff had a tunnel ram.

BTW, long before it happened, I was told all engines would basically have a TR manifold. Was I was told is correct. Most everything today that is a V-8 layout has a TR on it. They just laid it down to get a hood on it! One of the places that EFI helped (think about the old max wedge crossram stuff).

I think Mark will help me with that(jetting). He's the man.

Then it will idle like a kitty and roar like a lion.

That sounded better in my mind that when I typed it.

Is this thing going on the dyno? I'd love to see the numbers.

You need to remember that the right foot controls the throttle especially on the street
Some things feel so good you just can't help yourself from over doing those things

I would believe two 750's would be good but I would think two 660 Center squirters would work better.

https://www.holley.com/products/fuel_sys...rs/parts/0-4224

So true

LOL! Yes,I agree

Yes, I hear nothing but good about them. The carbs will be poked thru the hood so need to look tough as well and the gray and black ultras xp do that.

Yes going to the Dyno but not with the t ram. I'm taking an 850 and an 1050 dominator.

I for one can't wait.

My combo is near the same and I have two BG 750's on mine and wish I had bought the 850's.

When my 451" DartSport was running in the 10.02 area with a best of 9.96 in good air I had a 1050 Dominator(quicker than smaller carbs I tried) on it. I switched to an M1 TR with two 750 Quickfuel double pumpers and the car ran in the 9.90 range with a best of 9.89 and it even ran 9.90's on hot days.
I loved the tunnel ram and it was more mellow on the street than any single carb I had on it previously.
The only downside was that it drank twice as much fuel.

By the way, I was running the MP 590 purpleshaft.
OhioGTX ran a TR on his big B-body and it went 9.70's with the Comp 650 lift solid cam.

Yeah, that sure is true. My 8 gallon fuel cell used to last through 3 time runs and 3 rounds of racing. Now I'm filling it up after warm up and time runs.

Yea it got kind of annoying lol, but I loved that TR!

I ran a tunnel ram on the street with a matched set of 750 dp's with no problems except spark plugs fouling probably due to low RPM's. On the track they worked great

OK that's nice to know 750's won't be too much carb. With the tunnel ram wont be ready in time for Dyno day, but I can put it on a chassis Dyno when its done.

Bill Jenkins (if anyone but me remembers the fastest small block engines on the planet at the time?) remarked 40 years ago that the carburetors and plenum volume that produced the highest steady-state power on the dyno are at least 10% too big for best acceleration.

I'm running two 660's that flow about 690 each. They have 50 cc pumps. They are on a 440 that is an old school build. Still haven't gotten all the bugs out yet. This is the best pair of carbs I have had on this engine yet.

Many racers out there that like their 660's. I asked Mark about them and he didn't have much to say. Besides the center squirter and straight boosters what makes them so different or better than a 650dp?

Well, if the 750's are on the edge of being too small than they should work well on my combo.

You'll be happy with 750 double pumpers. I don't know how necessary it is, but my Quickfuel carbs were custom calibrated for a TR and had wedge shaped floats for a TR with sideways mounted carbs. They were pretty much spot-on right out of the box.

Cool! Do you know what qf put in them for IFR and main jets? Square jetted or PV out of the box?

I have had very good luck with custom QF carbs over the years. ALthough, they are under new ownership now correct? I have not bought one since the change, but I would be curious to know. I still use a lot of they're parts over Holley stuff.

I took the road less traveled and used a pair of 850 thermoquads. 18 dyno pulls later they were dialed in. They made about 40 hp more than a 1140 dominator on my 605. Torque numbers were better from the start of the pull all the way to the end. IF I drive it nice, I've been able to see 10mpg. I'll never go back to a single 4bbl. Dave

I no longer own the car, I know I ran them square jetted with no power valves but I can't remember if they came that way. I'll try to see if new owner still has the build sheets for the carbs.
I'm sure he'll know what jets are in them.

Dragula, I did not know Quickfuel was under new ownership. I wonder if some of the guys stayed.?

Just curious to your specs. Mark said he would help me out with the tune on the ultras. Thanks

sounds read good. thanks for all the good info guys. now i'll get these ordered

Just put a pair of 950 TRE carbs on my 528 street strip Cuda and Love it, still have some bugs but picked up about 40hp over dominator and went 608 rwhp.
Did have a little trouble starting it but I turned off the start retard so it's all in 34deg and now fires up great, I would also say it feels better on the street.

Go for it.

I believe it is simply that they are well calibrated to a tunnel ram OOTB, and the 1:1 linkage works well for fuel distribution

Once you say "no power valves, no vacuum advance", a question about mileage is pointless.

who cares about mileage. i just want to go fast and look good doing it. i finally got the carbs ordered. what a pain that was. got them refurbished for $650ea thru jegs, but will be drop shipped from holley. i would have liked to try the 660's after reading all the good reviews on them, but Marks responce on those left me thinking he didnt think much of them. just my opinion.

oh, these will have pv when street driven and square jetted while at the track.

That's how I did it too, runs a little smoother with the power valves and they're easy to throw in there with the carbs mounted sideways.

I have bought parts off of you before Dave. And enjoy your posts. I just built a pump gas 572 hemi. I used a modman intake with otb 750 eddies lol. Guess I'm different huh? Health wise, i'm going down quick, so I wanted something simple. I had it dyno'ed though. It made 740 tq @ 5200 and 787 hp @ 5900. I'm doing this under a 69 roadrunner airgrabber hood. So it was costly to have an aircleaner built for my car. Not many around running a modman with an airgrabber.

Either way, it sounds like you are on the right path to having a fun cruiser plus a great track car for weekend fun. I'm glad to see you were one of the top posts to read right when I went into Unlawful's place.

well thanks for the kind words Al. Sounds like you have quite the power plant under the hood. That's some ponys there. I know an engine builder near me that put together a 409 chevy BB with 2 500 edelbrocks and it ran real good on the dyno.It went into a 61 or 62 bubble top impala. I think that motor n/a made in the mid 550hp range. He liked edelbrocks for dual applications.

Yeah. Should be easy to work on and i'll need that to get this thing dialed in. I'm going to concentrate on getting the 1050 dialed this summer and then next spring I will get on this t ram. If the engine happens to go south for what ever reason I will get a 470BB together and use the 750's with a t ram on it.

I run two holley dominators and have for about 28 yrs. They run great on the street, only need transition circuit jets and they work fine, gets 10-13 mpg and never foul plugs. Jetted square and no power valves

whats your combo sanchez?

436 inch amc, indy heads, 12.4 compression .794 .747 278 286 @ .050 edelbrock tunnel ram, 69 javelin 3480lbs t400 dana 60

But I also ran same intake carbs on it when it was a stock 401, and when it was 401 with iron heads and flat tappet cam

What list number Dominator are you using?

80186, started life as 750, getting ready to change boosters to 1050 style

I have had and used a bunch of different Holley 1050 CFM Dominators for single four barrel bracket motors over the years, some worked good and some didn't I have a pair of Holley List 9375 now on a BB Indy tunnel ram that I'm looking to use soon, one of them has had some mods done to it before I bought it so I recently bought another one hoping it is stock so I can use the two stock ones on the manifold I'm going to do some engine dyno testing soon on single dominator intake manifold so I wll test all three of them one the same motor the same day to see the AFR results One needed one jet size differents to get the same AFR in past testing Thanks for the help

Those I would convert to 2 circuit