lars

Thought I’d share some dyno results on a 355 SB buildup (.030” over 350). This is a good street engine with a 1050 4500 Holley Dominator on it (yeah, my carb’s too big…). We installed a nice big CompCams mechanical flat tappet cam (yeah, big solid cams aren’t for the street), used a pair of Dart Iron Eagle heads (right out of the box – no grinding) and ran a Super Victor intake (yeah, single plane manifolds don’t work on the street…). The dyno pulls were made with the Dominator, but we have since run the engine on the track with a 750cfm DP to document that the car slowed down .2 on the ¼ with the smaller carb (yeah, it probably needs an Edelbrock Performer 600 cfm). Car runs low 12’s, and it’s an incredible street driver. Peak power is 433.7 horsepower at 6200 rpm. The dyno we used this time wouldn’t pull smoothly below 4900 rpm, but I can attest to the torque and instant throttle response on this engine at street rpm at and below 3000. This is just too much fun..! The Excel spreadsheet gets a little jumbled when I paste it into the Forum format here, but I think you can make out the columns and numbers:

Listing of: (memory data)
Channel Group: Corrected Torque and Power Page 1
Printed on Mar. 29, 2004 12:24:04
Test Description: Accel. Test - 300 rpm/second

EngSpd STPTrq STPPwr BSFC #1 EXH T
RPM Clb-ft CHp lb/hph deg F

4900 390.9 365.6 0.57 1500.0
** 5000 390.8 372.2 0.59 1500.0
5100 389.0 377.8 0.65 1500.0
5200 389.6 385.7 0.64 1500.0
5300 389.1 392.6 0.63 1500.0
5400 388.1 399.1 0.63 1500.0
5500 388.1 404.8 0.62 1500.0
5600 383.1 408.4 0.62 1500.0
5700 383.2 415.9 0.63 1500.0
5800 380.7 420.4 0.61 1500.0
5900 379.3 426.1 0.58 1500.0
6000 376.2 429.7 0.58 1500.0
6100 370.8 430.5 0.59 1500.0
6200 - 433.7 0.63 1500.0
6300 - 431.4 0.66 1491.0
6400 379.8 425.6 0.66 1479.0
6500 336.6 420.1 0.76 1453.0
6600 330.3 415.1 0.77 1432.0
6700 320.7 409.0 0.76 1394.0
6800 315.6 408.6 0.78 1344.0
** 6900 305.4 401.0 0.76 1285.0

** Range: 5000 RPM - 6900 RPM
AVG: 6263 470.2 410.9 0.629 1496.0
MIN: 5000 305.4 365.6 0.57 1285.0
MAX: 6900 390.9 433.7 0.78 1500.0

Chuck Harmon

As long as you admit that the carb is too big, the intake and cam to be too radical, I will let it pass. "I knows what I knows, don't confuse me with facks!"

Chuck
:D

lars

I admit it. Actually, I believe that the reason the car runs quicker with the 4500 is only because of the superior design of the Dominator allowing very smooth and uniform air flow - not due to the size per se. I think this engine would produce better power and throttle response if a smaller carb were used that had the non-turbulent flow characteristics of the 4500.

Ozzie71

G'day Lars
Does that mean that you would recommend a 750 Dominator over a 4150 Holley/demon/Proform etc for a mild 350??? Have you done any testing with the 750 Dominator???
I have been chewing over Carb choice for some time and I enjoy reading your posts very much. You have certainly given plenty of food for thought.
Cheers

Mick

The Dude

Dude, you really gotta start paying attention to The Rules. Everybody knows that engine won't work on the street. Whazzamattawitchooyou, boy? :D

NHvette

Well, after plowing through the witty sarcasm - which I enjoy ....

It looks like you chose components that complement each other well.

In other words, I hope that people don't read into your subject - that they can
slap a 1050cfm carb on their L48 and expect any noticable improvement.

Also, I like that you admit that (if both were Dominators) there may be no
difference between the 750 and 1050 on this engine.

So, I would definitely agree with you ... big CFMs are not necessarily bad on SB engines.

:cheers: :seeya

Gordonm

What are the specs on the cam? I love this debate over big carbs on small cubes.

427Hotrod

Lars...you're killing me!!

And as I told you, you're going to mess up all these folks notions they've picked up out of all the magazines that constantly tell you smaller is better.

A well matched combo is just that. I strongly believe in giving a motor what it wants.

I've told everyone for years that a 750 DP will run perfect on anything from an inline 6 cylinder to a mild 454. It just doesn't care.

I used my homebuilt 1050 Dominator on my relatively mild 427 for years and was always told it wouldn't work. It still is on my 540 and is a little small for it, but I'm cheap. I can't tell you how many dyno operators have commented on how smooth it runs through the range even from very low rpm. You just have to set them up well just like any other carb.

I did do a back to back test with a 750 Dominator against my 1050 on my 427. I had rebuilt/tuned it for a buddy of mine and wanted to make sure it was right before I gave it back to him. I drove it on street first and it was fine, but you could immediately tell it was slower than the 1050 even in the midrange. At the track we tried both carbs and it was down .3 and almost 4 mph on the same night! It just didn't have the performance.

The last time I had my 540 on the dyno we did some back to back testing with my 1050 against a killer 1400+ cfm Dominator. I mean this was an unreal carb that was borrowed from a VERY well known Pro Stock racer. He had converted it to be used as a single 4 deal instead of tunnel ram. The under 5000 rpm power was down and curve was a little jagged on the A/F ratio and BSFC, but after 5000 rpm it was so dialed in it was ridiculous as far as fuel curve. It just stayed perfect throughout the pull to the 7000+ rpm range.

The interesting thing was that it only made 6 more HP at the extreme top end. It flowed 1178 cfm at peak power as compared to the 1050 that flowed 1173 cfm. The issue was that the intake/engine combo was just not going to flow much more air without major changes.

It might have been quicker than mine due to the perfect fuel curve, but overall I was happy with the "smaller" carb that wasn't worth $5K!!!

So, yes, all motors like more air. And yes, there is a limit to what it can flow. But the idea that you want the carb absolutely maxxed out when it reaches peak HP/rpm is ridiculous. That's why I disregard many of the formulas. Great theory, but go try it and see what happens. Lars did, and so have I. If the results don't match the theory,it's time to re-look at the theory and learn something!

Now....let's talk about solid lifter big cams, big heads and single plane intakes! In fact lets talk about tunnel rams on the street......

Just 'cause it don't work for you, doesn't mean it won't work. It just means YOU haven't been able to make it work and need to play with it some more!


Great post Lars! I need to look you guys up again...I've been working almost every week in Denver for the last few months and will be for awhile longer.


JIM

DJ Dep

Ahhhh...proof positive BIGGER IS BETTER!!! :lol: :lol: :lol:
Now you need to dump the mouse motor and get to work on a a REAL engine ;)

Dep

gdh

Lars, were you using the 292S?

lars

It's a 285B-6 drag race solid CompCam.

lars

Hey 427HOT -
You need to stop by the CCC HQ again - the garage has been completely re-done complete with a bar. Your Texas flag is proudly displayed above the beer tap, but your signature faded out - you need to stop by and re-sign it! I'm currently working on the world's slowest 427 67 Vette, and I think the solution is a HUGE cam and a HUGE carb.... :lol:

garagedweller2

Got cam specs?

cardo0

Okay lars I'm a believer now. :yesnod: Anything special about the boosters? I bet there's some lar's majic in those boosters.
BTW received my Q-jet today and looks great! Can't waite for start-up. Thanks again.

Now I do have a related question here. I bought two Edlebrock A/F monitors and had a ring fitting (bung) welded on each collector (for the O2 sensor). Planned on installing LED indicator boxes in radio hole but running out of room. Can one be good enough for accurate tuning? What do think? Install two at all costs (I don't care much about originality or stock looks) or is one A/F on only one side good enough? :rolleyes:

verskel

:thumbs: ......let's us know how it turns out. :D

355torana

Hey guys just came across this post I know it's very old but so is my engine haha I have a Holden 355 stroker with 11:1 comp, ported heads ,624 lift solid cam , Harrop single plane manifold 38deg timing etc 4500rpm converter in full manual th400 with 411 diff gears currently running Proform 750DP carb in 1280kg Torana wanted to put a 1050 dominator on any thoughts

Bikespace

We're going to need to see pictures of your Torana. Please start a new thread!

vettebuyer6369

Consider starting a new thread in these cases.