All of the mentioned companies have good products and make good power in the right hands and on the right combos....

Well stated: couldn't agree more.

So, Dominic... if I come up with a 4500 intake, you gotta "loaner" carb for me to test?

I don't even have a carb on my junk now since a customer needed one so I will build me a billet 1150 next week but sorry nothing to loan out. You have enuff skill to mod an old dommy and find out what you've been missing.......

/

Sorry to bring up an old thread, however a friend just called and told me about it so now seems like a good time to join the forum and fill in some gaps regarding the twin blade carbs. I'll share as much information as possible and hope I don't step on any rules. Sorry in advance for the long post.

btw: I like the info on here, seems like a group of sharp guys.

I am the designer and patent-owner of the 'twin blade' carb (Carburetor #D748149), the 'upper fuel jets' (Fuel Jet Tube #10036357) and the '2-piece fuel bowl' (Fuel Bowl for Carburetor System and Associated Methods #9404442). The first 2 patents are used in all twin blades and the 2-pc bowl is a popular option.

There are two (2) companies licensed to manufacture, sell and/or use the patents shown above: Phelps Machine R&D (PMRD) and Decker Machine (DM Performance).
I also designed & tested what is now called the BX4 Extreme for BLP before leaving in order for them to have a new design. It was important to me for the employees there to have success and also allowed me to do a direct comparison between the 4-bbl and the twin blades.

A common mistake made when calibrating a twin blade is to underestimate the air flow and booster signal. (I made this mistake with the first few...) I get it. It's a small, lightweight carb and seems unassuming when looking at it. Most try to use their standard 4150 calibrations (850, 950, etc) with maybe a tweak or 2 and it's just lean all over. These carbs flow the same amount of air as a 4500, so it makes sense to calibrate it like a 4500. After doing this, everything will fall into place. And for the record; I've tested these things against 4500's for a long time now and when both are well calibrated, the twin blade nearly always outperforms a 4500 with reasonably close air flow. Tony Morris (an agent for PMRD) is having great results when replacing 4500's with twin blades on a variety of fuels, engines and cars. There is also a significant weight difference.

The twin blades also have better fuel distribution than 4-bbls due to the shape. I could type it all out to explain, but I made a short tech video that explain why this happens. A new builder in TX recently built a 1400 twin blade and tested it on his 572" Mopar dyno engine. All carbs require a 2-4 jet size difference from side to side on this engine, but the twin blade made the best power and best afr readings when jetted straight up. We've seen this over and over on nearly all cars and it's due to the venturi/throttle bore ratio and shape.

Drivability with a twin blade is one thing that everyone likes. There is normally a significant increase on the power curve from below peak tq to peak hp over a similar sized 4-bbl. It's a well shaped curve with no peaks or valleys. These carbs have become quite popular with the road-racing crowd due to the smoothness and I have a close friend who replaced his EFI unit with a twin blade on his C3 resto-mod Vette. He said it drives better than it ever has now.
Let me know if you have any more questions. Thanks for reading...

Mike

Patents
Twin Blade Info
Twin Blade Physics

Welcome to the board and thanks for brining some solid information. It would be great if you could post some links to the dyno tests, even better some back to back tests on a car.

I ran one on my Dart for a short time and it was super responsive and ran pretty well after putting my tune up in it but I sold it and went back to a 1050ish Dommy and was much happier. Not that it's a bad design at all and actually it was TOO responsive a peaky down low making traction a b%^&h and why I always go bigger than some on cams and carbs to move the power band up some and making traction less of an issue, kinda like adding duration to your cams......

I'm converting some dyno data files to graph for visual reference, but it will take me a day or so. In the meantime, here are a few recent testimonials and a facebook link: TMC FB

"Paul Rebis Sr
I’m so happy to see the progression these twin blades have come. I remember trying them back in 2012 maybe and they were ok. But I still chose a dominator over one. But if someone asked me that same question now I would say no way in hell. That upper jet is a game changer. And the throttle response of the twin blade is about like fuel injection. I’ve never had a carb that you see the results every little change made."

"Thank you Paul Rebis Sr!
Had a awesome weekend at Bradenton Motorsports park for the drag race for a cure race. Car was insane. It’s such a pleasure to drive this car again. Been testing a lot of different things. Engines. Heads and most importantly CARBS ! I want to thank Tony Morris for helping me with the finest parts in carbs. This twin blade carb is the best most tune-able carb I’ve ever tried. I have a carb from every carb manufacture there all great but this one is amazing. If anyone needs a carb I would get on board before everyone else has one and your racing them Every round. I almost won 2 races in one day. But fell Short and had the worse tree all day .019 to Gage Burch .006 were both dead on. And that isn’t going to get it done congratulations gage Burch"

"BATTLE OF THE TWIN BLADES at DRC!
What a great event put on at Bradenton this past Saturday, the DRC event was a rescheduled race from a few weeks back due to rain and we have to thank David W Jr Pike for doing such a good job and BMP crew!
TMC had to drop off some carbs new and converts, and also be on hand for Mark Mullins who was trying out a TB-1400 alcohol twin blade. Once arriving TMC made a few adjustments to the carburetor on the Vega and off Mark went for his first time run with the twin blade.
Mark had been running the Vega on gas for a while, but couldn’t quite get it where he felt it needed to be and had asked Tony from TMC what he thought about switching back to alcohol on the Vega which he had tried before, plus it would make it easier on him as the Chevelle he runs also runs on alcohol, Tony offered to build a twin blade and let Mark test it at this event, this would give Mark the chance to see if it would improve the way the car reattached and how consistent it would be ove the course of the race.
The best the car ran on gas a few weeks back in September was a 5.70 @120mph, this is with a BBC with 560ci and 10.5:1 compression. The first pass went really well with Mark running a new PB out of the box a 5.470 @125.37 that a over .2 gain and 5 mph, everyone was very happy with the improvement!
For the second time run a little less jet was taken out to try and gain a little more heat on the run, this would have the same 60ft within .001 and run a 5.48 but it did have a sight stumble so that needed to be addressed before round one, a small idle bleed change was made and we were ready.
For round one Mark picked a 5.48 for his dial in but ended up breaking out running a 5.468, after talking back in the pits we figured why the difference in ET and moved on to round two.
In round two Mark ended up having to run another TMC team mate Paul Rebis in his red Nova, both car we’re running the same TMC twin blade, this turned out to be a great race with Paul getting the upper hand on the start line although Marks wasn’t that bad, Paul .006 was going to be hard to beat when Mark pulled a .023 but still managed to run dead on running a 5.469 to Paul’s 5 .668 on a 5.65 dial in!
Mark won’t be giving the twin blade back anytime soon as he has chosen to leave it on the Vega permanently!
Paul would end up going all the way to the final and lost to the super wheelman Gage Burch in his Mustang, congratulations Gage, but Paul did end up winning in Extreme Hot Rod!
Also on hand racing was team mate Todd Osting who made it to the semi’s, team mates Jim Walter and Billy Dunn all supporting Twin Blades!
We like to thank Mark Mullins for trusting TMC again as always for his carburetor support and helping us make a better product!"

"Congratulations going out again to Billy Highhouse and team who tonight took the win in the race of champions in S/P at the Rock in NC!
Billy runs one of our TMC-1400 Twin Blade’s on alcohol!"


The dyno sheet is from a 2-day session on an inertia dyno with a very competitive 409" BBC pull-truck engine. The 3rd column is the best pull with a well known brand 2.325" throttle bore 4-bbl and the 10th column is the best pull with a slightly smaller twin blade. I'll get a graph up later. 409bbc

I understand and you're right, 1050 Dominators are good carbs. The twin blades can be responsive down low or calmed down and still run well in the mid-range and up high. Personal preference is important...

Welcome about Mike!
Good to see you posting.
We have been running one of Mikes Twin Blades for a couple years now- haven't found the end of it yet , every mod we have made to engine, we still had plenty of carb and tuning has been easy and accurate .
I take data so i can look at the curve each run.
Yes to offset jetting on BB strokers , we are 3 jet sizes ( Max Jets - not holley) different between banks .

Yes to responsive, boosters come in quicker than other carbs, have to watch for being rich on leaving ( footbrake car) and boosters come in fast enough its easy to have to long a pump shot.
Rpm recovery is really good as well, afr's don't get mushy on the rpm drop, graphs are clean .
For class racing where carb limited to 4150 style - its a great way to get cfm if needed .
We had Wilson work the intake, and, with one of Mikes mainbody's to reference with, they build the spacer for the combo and flowed everything together - really worked out well.

A big thanks to Dom of ThumperCarbs setting us up initially , throwing a tune in and providing his usual package of jets and bleeds, as well as PhoneTech time helping us get dialed in initially in some nasty D/A.


Imho: Quality product, no issues , easy to tune with differing fuels , no negatives - one just has to learn the Carb I guess as it does come up on boosters- Quick!

Blessings all

Absolutely Mike and it is no doubt an angry and super responsive sucker and part of that was I let the builder at that time pick the cfm and it was also a 4150 series on top of a heavily modified intake/adapter deal set up for my usual 1050 Dominator. Never got to try a Dominator at that time as we parted ways but maybe a pair of twins for my 470 BB are in the future........I'm willing to try em on my t-ram after I get my next runs in with the billet 650's then hit you up or my #'s in my sig and call anytime Mike it would be a pleasure talking with you sir.......

You are welcome Rusty and the perfect guy for tuning on one of those since most don't run em and you being you, is the reason I sold it to you in the first place knowing we could both learn some real world stuff together and share notes....

Hey Rusty,

Thanks for the welcome, this is a good forum! Appreciate your thoughts on the twin blade too, it sounds like you've got it well figured out.

fwiw: The boosters react quick and strong due to the favorable venturi to throttle bore area ratio - and the lack of a low pressure area between the bores of a 4-bbl. [Booster technology has improved a lot in the past couple of years as well.] You can tune around the active boosters with emulsion circuit and/or booster design, however most like the responsiveness, calling it similar to fuel injection. The combination also allows one to to use a 'bigger' carb (more cfm) than normal because the boosters will remain active due to the favorable shape and ratio. The larger carb produces more mid to upper rpm performance because of this. Like most things in racing; it still comes down to physics...

With a twin blade venturi...What is currently available in anti-reversion plates for more line-of-sight intake manifolds?

Sounds good Dom. I have a thought: Get the 650's dialed in as good as they can be on your 470 and let that be the performance baseline. Then let's spec out and dial in a set of twin blades for it, describing the setup, changes, reasons why, etc on a dedicated thread on here and compare the results of both setups. Or we can do a single 4-bbl setup. I'm game for either. Might be fun for us and for those following...

Jim Parr in Texas has talked about making some TB anti-reversion plates. I am unsure what the status is though. We tested at least 4 different spacer-styles during R&D on an inertia engine dyno including anti reversion on line of sight manifolds and a simple open spacer was as good or better than anything - but I am not aware of any meaningful track comparisons. There could be something there, I just don't know.

Mike, with the twin blade base plate, are the bore centers the same as 4150 stuff (same bore centers, just opened up to two slots) or something completely different?

Cheers

Alan: There are 2 different sized baseplates. The 'smaller' version has the same footprint as a Holley 850. These carbs vary from 650 to 1230cfm, depending on main section/booster arrangement. These carbs will fit any 4150 or 4500 intake manifold.

The 'larger' baseplate size is between the 850 and a 1050 Dominator with an opening of approx 4.375" square. These carbs vary from 1200-ish to 1620-ish, depending on main section/booster arrangement. These carbs will bolt onto any 4150 or 4500 intake manifold, however if used on a 4150 manifold, the opening will need to be enlarged.

I'm still working on getting to the track but it's pushed back farther every time I work on the POS but hopefully soon the 2 twins will be right after that for comparative street and track testing.....