Whats the difference ? 4150 question !
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Thanks you
yellow rose
Overnight Sensation
yellow rose
Overnight Sensation
LOL...you know Dom is going to say it needs a Dominator, and I wouldn’t disagree with that!!
Glad he's on moparts cuz I don't do facebook
33IMP
Well-Known Member
Agree with PRH, marketing strikes again. Holley came out a while back with a new hi-zoot carb that they called a (something) 950., hoping the customer would assume it was a 950 cfm carb. It had the same throttle size and venturi size as a 750. Cause it WAS a 750. The 950 name was marketing.
Thats the classic hp 750 main & 1.75 throttle plate
PRH
Well-Known Member
If your combo has enough cylinder head, intake, exhaust, and camshaft to still make good power in that rpm range, along with enough stall to go along with it....... then I’d say a 4500 carb would be a good choice.
Where did you find a super victor for a low deck ?
My low deck has Stage 6 Mopar heads on it. They are narrower than regular heads so I can use a RB intake. If I were to put these heads on a 440 I would need intake spacers to use them. Kim
Oh, okay....dang it !
Thanks Kim
Your parameters come out to 904cfm@.95%VE but you don't know the VE at a given rpm. Our 589 dyno pull shows our 950HP with 1.375V and a billet 1.750 t/bore plate pulled 104.4%VE@5400rpm and was using 957cfm according to the calc, but its just a calc...at 6000rpm VE went down to 96.8% but was pulling 989cfm in theory.....at 6000rpm the carb pulled 2.0"Hg of vacuum, at 5400 it pulled 1.7hg. That carb made 695hp from 5500>6000, a 1050 Dominator was also tried which made only 3hp more and around 0.6hg, the carb could've been rubbish but we don't know.. a lot to get your head around I know and I'm only 98% with it myself. Every one will tell you an engine of that size should have an 1150 Dominator on it at least, not always the case, if we ran more rpm, had a better converter (4500+) and more cam perhaps, but this car is street/strip.
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PRH
Well-Known Member
Actually..... it’s not a 750.
Before the “HP” carbs existed, a very popular carb in the circle track world that was sold through a bunch of different carb modifiers was to take a 750DP, cut the choke tower off, blend the top, then taper bore the bottom of the carb body from the stock 1-11/16” up to 1-3/4”, and then use an 850 baseplate on it.
The HP950 is basically an ootb version of that concept, only with an improved air entry shape.
The flow about 860.
A “750” has a 1.375” venturi/1.687” throttle bore.
The original HP950 has a 1.375”venturi/1.750” throttle bore.
yellow rose
Overnight Sensation
LOL...this is one reason I say not to select a carb based on CFM. It’s just not really representative of what you may or may not be getting.
Venturi diameter first, throttle blade diameter after that and the CFM is what it is. The more “modern” carbs with the better shaped main body will flow more air with a smaller venturi, and its cleaner, smoother air.
In a full race car what would be the issues of using a 1.56 venturi & 1.687 throttle bore, downleg booster 830 hp on my 471 stroker?? it's a smooth inlet main body with removable air bleeds.
Would the velocity be slow?
PRH
Well-Known Member
Uuuhh....... that would be a straight tube...... no venturi.
Krooser
Building Chinese Free Engines since 1959...
I will.be running a single Stromberg 97...…
For your lawnmower ?
PRH
Well-Known Member
I haven’t run one of those on anything in ages.
The way I remember them is....... they just weren’t anything special.
Some other stuff I tried worked a little better.
So, based on those experiences, if I’m buying a carb....... I’m going to buy something that’s “hopefully” a little better.
But that really has no bearing on how good one would work on your engine......especially if you already own it.
If you own one, just try it.
A couple years ago I had a motor on the dyno and the owner had brought several “fancy” built from scratch carbs to try on it.
All were the new type bodies, one had the billet 1.600 x 1.750 main body outfitted with some special annular boosters, all had billet metering blocks, etc.
None of them had great fuel curves, and the balance between part throttle and wot was not very good either.
I had brought my dyno mule built-from-scratch HP950....... “just in case”.
It was obvious it was going to take way way more time than we had to even get one or two of them really dialed in........ so we mildly tweaked one that was “closer” than the others to see about getting a number from the motor.
After some playing with the timing and spacers, it put up a pretty decent number.
When we were basically done for the day, I put my HP950 on to get some kind of caomparison to a known carb, which is really nothing special in the HP making dept.
I used the same spacer and timing we were running with the other carb(which was a 1.520 x 1.750 downleg)....... and it(the HP950) had the best balance between part throttle and wot....... had decent A/F ratios without needing giant jets in it(which all the other carbs needed), and it made slightly more power than any of the others....... despite being the smallest one tested.
That’s just a long story to say....... you don’t know how good any of them work without trying them.
The 1.600 x 1.750 body with the fancy annular boosters was the worst carb we tried.
Very very rich at part throttle........ and too lean to make a pull at wot.
Added a bunch of jet to it, which made the part throttle even worse, but the wot was still too lean to pull it into the upper rpms.
That was the second carb we tried...... after we saw how far off it was, we moved on to another one.
Part of why I wanted to put my 950 on the motor was to verify there wasn’t something screwy going on with the combo.
Up to that point, all the carbs we tried were quite rich at part throttle...... and pretty lean at wot(especially considering how big the jets were that were being tried).
My 950 didn’t require any jet changes and had normal a/f ratios...... and part throttle was fine.
It was the carbs that weren’t too good....... the combo was fine.
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interesting.... what I found with my 4825 (1.48 venturi/ 1.79 throttle plates from a few pages back) is that if the DA went below 800ft it would go lean. Of course at the track all we had were jets and 99 was the largest we had.... no bueno. This carb still used power valves too. Prob would have looked into it more, but we moved on to a 4500.
PRH
Well-Known Member
There doesn’t seem to be much love from a few of the carb builders for the 1.600 x 1.750 Holley Ultra HP carb or body.
I wouldn’t mind trying an untouched one on the dyno with an “appropriate” build ....... just to see for myself...... but I’m not interested enough to spend $942 for that experiment.
To me, an appropriate build would be something over 500” making solidly over 700hp.
I was looking through some dyno sheets.......
I had taken a Mighty Demon 850DP(those are 1.560 x 1.750) in on trade for something a few years back.
The tune up someone put in it was just dumb(and wrong).
I put it back to stock, and then tweaked on it with a few different motors, and it ended up being a pretty good dyno mule carb.
I had gotten to a point where I was pretty “carb rich” and decided to thin out the herd....... and that was one that went to a new home.
I often feel like I should have kept that one.
The best working ootb “large venturi” 4150 carb I’ve used was a QFT Q-1050 down leg on a street 572 with EZ heads.
Those are 1.590 x 1.750.
I think we may have done one jet change on it, and it was good.
It made a few HP more than my MD850.
I wouldn’t mind trying an untouched one on the dyno with an “appropriate” build ....... just to see for myself...... but I’m not interested enough to spend $942 for that experiment.
To me, an appropriate build would be something over 500” making solidly over 700hp.
I was looking through some dyno sheets.......
I had taken a Mighty Demon 850DP(those are 1.560 x 1.750) in on trade for something a few years back.
The tune up someone put in it was just dumb(and wrong).
I put it back to stock, and then tweaked on it with a few different motors, and it ended up being a pretty good dyno mule carb.
I had gotten to a point where I was pretty “carb rich” and decided to thin out the herd....... and that was one that went to a new home.
I often feel like I should have kept that one.
The best working ootb “large venturi” 4150 carb I’ve used was a QFT Q-1050 down leg on a street 572 with EZ heads.
Those are 1.590 x 1.750.
I think we may have done one jet change on it, and it was good.
It made a few HP more than my MD850.
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The gto 389
Member
Hey guys , I have a 10.5 1 440, ootb edy rpm heads xe 284 cam new brawler 750 dbl pumper, runs great, very good response but I just kept thinking maybe I needed more carb? So I bought a new brawler 950 race carb , haven't installed it yet what can I expect ootb results?
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