Is this possible ?

Guys a fellow race buddy just dynoe'd his new P-51 headed 545 about 13-1 comp ratio, I think a comp cam .726/.726 around 270/280 @ .050", 4150 Victor. 850 Demon carb. C12 race gas.

It made 797hp ? I though for sure he would have needed more carb like at least a 1050 dominator. Is this a happy dyno ? I didn't think the Demon 850 would even get to 750hp. As you know most of our BBF engines like the big carbs. Am I missing something with these smaller carbs ? or can we just say that the Dyno is a tool to use to see if we gain by changing components and leave it at that. Oh ya by the way there will be no way to confirm HP by weight/times as this is for a mudracer with ever changing pits and conditions. I am just curious.

Thanks Mark

i'll go out on a limb and say "YES...easily"

790 hp for a 545ci, it better make that

I'm thinking that the question is whether or not a 4150 base Holley 850cfm carb would be enough for that hp output. IMHO the guy is leaving some hp on the table with a carb that small. I have a buddy that has an almost identical engine to mine and I can tell you that my Dommie fed engine will get all over his stuff with the smaller carb.

I think rpm has a lot to do with it too.

I have seen this before. We switched a 1150HP Dom carb out for my 1000cfm 4150 prosystems carb on a guys 565 bbc from Sunset Racecraft and it picked up in the 1/8th. This was in a Chevy II tube car that ran 5.20's. I think it was in the 950hp range.

I could see a 4150 picking up in the 1/8 but wouldnt it fall flat on its face at the 1/4? I think it may atleast but im no carb expert. just starting to learn the dommy vs square concept. loving the massive amounts of air the dommy feeds.

There are other things to kill a combo worse than a carb too small.


Put a dommy on it and a set of procomp heads and then you will have a huge turd.

richter69 wrote:There are other things to kill a combo worse than a carb too small.


Put a dommy on it and a set of procomp heads and then you will have a huge turd.

I think the carb would jump off the engine and hide somewhere screaming replace the heads!

Maddmattmustangs wrote:

richter69 wrote:There are other things to kill a combo worse than a carb too small.


Put a dommy on it and a set of procomp heads and then you will have a huge turd.

I think the carb would jump off the engine and hide somewhere screaming replace the heads!

richter69 wrote:There are other things to kill a combo worse than a carb too small.


Put a dommy on it and a set of procomp heads and then you will have a huge turd.

whats the most power someone has made with pro comps,on a 466 bb ford? anyone?

BOSS 429 wrote:

richter69 wrote:There are other things to kill a combo worse than a carb too small.


Put a dommy on it and a set of procomp heads and then you will have a huge turd.

whats the most power someone has made with pro comps,on a 466 bb ford? anyone?

A 557 made a whole whopping 658 ft lbs of torque with them as well as like 615 hp.

What is sometimes amazing is how much smaller or larger the carburetor has to be made in order to make a drastic difference in power or on track performance. One time messing around on the dyno with a Ford 460 engine that made 585 horsepower running with a 1050 Dominator we experimented with some different carburetors, just for fun. A 4412 two barrel(1/2 of a 4779 750 four barrel) made 425 horsepower. A 600cfm two barrel(weird old annular discharge Holley 2 barrel design unrelated to other Holleys yet still 40% smaller than a 600 four barrel) allowed the engine to make close to 500 horsepower! That's a lot of difference in airflow and while we were able to lose 100 horsepower the amount of change in carburetor size was much more drastic.

So, he would probably almost without question gain some power with a larger carburetor but it might not be as much as it would appear when looking at the airflow ratings of the carburetors.

A larger carb may not necessarily make more horsepower; it will however usually make more torque at the peak.
Once the inlet air pressure drop reaches a saturation point a larger carburetor no longer helps high RPM horsepower. Different engine combinations have much different "ideal" intake pressure drops. When you get close to 2 inches hg it is almost a guarantee it is too much drop.
From 1.2" hg to 1.4" hg usually won't matter and, in some cases if the engine is overexhausted the higher pressure drop will actually creat MORE flywheel horsepower.
The engine needs that extra exhaust scavenging at peak torque but not upstairs at peak horsepower when the torque is diminishing.

It's just another balancing act...!