OK, I give up. Help me pick out a new carb for my combo.

-
LXguy

LXguy

Well-Known Member
Joined
Jul 23, 2008
Messages
2,302
Reaction score
109
Location
Champaign IL
OK Guys, I'm having a helluva time choosing a carb, and I don't seem to get anyone serious on the phone when I call around.

Here's what I've got now:

5.9 Magnum stock shortblock.
Iron Ram (EQ) Magnum heads
RPM Air Gap intake
1-5/8 headers, 2.5" exhaust with mufflers.
Transbrake 904, with 3800 stall.
4.11 gear (switching to 3.91 as I don't have )

Car weighs 3270 with me in it.

Currently has a 670 Street avenger vacuum secondary on it. I want to put on a double pumper.

Max RPM with the 670 is about 6300. Car typically runs best shifted at 5700 RPM.

Car has run a weather assisted best of 11.79 @ 111, but had to let off shortly before the trap as I've got too much gear. It 60s at around 1.6 consistently, but car goes, then bogs slightly on launch. I'm pretty tired of trying to tune the secondaries to eliminate the bog.

I'm thinking a 750 double pumper would be a good choice, but all the
calculators show 650 to be more optimal. I'm not hung up on numbers but don't want to miss out on power or buy twice.

Anyone have any recommendations based on a similar combination? I would like to keep it somehwat streetable, but it doesn't necessarily have to have a choke.

Thanks for any help!

Steve
 
Holley 750hp or 950hp

The CFM calculators are GARBAGE!

I bet if you put a 750 it would run good, put the 950 and it would pick up ET and MPH.

With a transbrake you should be leaving with it matted to the floor.
 
call Damon at Diamondback and give him your spec,s and have one custom tailored to your set up. Even if you dont buy his he can give you some good advice. Also see his white papers for tuning.
 
crackedback said:
Holley 750hp or 950hp

The CFM calculators are GARBAGE!

I bet if you put a 750 it would run good, put the 950 and it would pick up ET and MPH.

With a transbrake you should be leaving with it matted to the floor.
Click to expand...

baghdad bob is never wrong....
 
650 Dp HP (4 corner idle) with a tall air cleaner as not to restrict anything!
 
crackedback said:
Holley 750hp or 950hp

The CFM calculators are GARBAGE!

I bet if you put a 750 it would run good, put the 950 and it would pick up ET and MPH.

With a transbrake you should be leaving with it matted to the floor.
Click to expand...

Oh, its matted.

950? Sheesh. That seems gigantic. Is that because of the dual plane intake?
 
I vote for the 750, can always tweak it later on to flow 930 should you go up in motor/power. One good thing about leaving on a trans brake is the carb is at WFO so its not quite so picky on tuning.
 
Dominator3.jpg
 
He choose a 950 because engines like to be able to breath super deep on the big end.

IMO, since your going 3.91 and the cars weight is closer to a street car...you can use all the high speed velocity and torque you can get.
 
LXguy said:
Oh, its matted.

950? Sheesh. That seems gigantic. Is that because of the dual plane intake?
Click to expand...

The 950 is just a number. It's got 750 sized venturis keeping the booster signal up/high.

Dual plane has nothing to do with the suggestion. Every engine I can remember picked up hp/tq running a 950hp over any 4150/4160 style 750.

Good that it's leaving matted. No accelerator pump/transition issues to deal with.

If that calculator was so accurate, why is it that the 360 I had ran better at the track going from a 750-950hp-1050 dominator when the perfect carb was a 660cfm IIRC... hmmmmm.. GARBAGE!
 
Where do you get the info on venturi sizes and the like? I can't find them on Holley's website.

Is it the throttle plate that makes it a "950" then?
 
skep:

I've been looking at the street hp. I take it you like it? Probably has better driveability than a standard double pumper?
 
Steve, i say the 750 HP street/strip & if your not running a cold air set-up, do that too.
 
Did you ever think it could be caused by your camshaft? What are the specs. especially the lobe seperation?
 
Call C&S Carburators i have there 800 aerosal vacume secondary for my 340, they build each carb to your specs and have a money back gaurantee on the aerosal carbs or check aout their web site
 
LXguy said:
skep:

I've been looking at the street hp. I take it you like it? Probably has better driveability than a standard double pumper?
Click to expand...

As far as cfm recommendations go, im no expert

as far as the carb goes though, I am running the exact same carb as skep and have to say i love it! bolt it on, set the idle, and go. The jetting was almost spot on, i lowered the primaries two sizes i believe, and i needed to up the squirters to a 35 front and back...other than that its working great

i dont think ill ever go to anything other than a box stock holley again...brand new carb you can tune yourself and not have to worry about other peoples work
 
mshred said:
As far as cfm recommendations go, im no expert

as far as the carb goes though, I am running the exact same carb as skep and have to say i love it! bolt it on, set the idle, and go. The jetting was almost spot on, i lowered the primaries two sizes i believe, and i needed to up the squirters to a 35 front and back...other than that its working great

i dont think ill ever go to anything other than a box stock holley again...brand new carb you can tune yourself and not have to worry about other peoples work
Click to expand...

I have to agree with you mshred, i just installed my 650dp & its damn near perfect.
 
JoeDust451 said:
I have to agree with you mshred, i just installed my 650dp & its damn near perfect.
Click to expand...

and if anything needed to be done, atleast you know what it would have to be and that you can fix it/ know whats done afterwards

i think all the carb builders and such are really hyped up...unless you have one very fast unique combo, id save the custom carbs for the rich dudes lol
 
mshred said:
and if anything needed to be done, atleast you know what it would have to be and that you can fix it/ know whats done afterwards

i think all the carb builders and such are really hyped up...unless you have one very fast unique combo, id save the custom carbs for the rich dudes lol
Click to expand...

Most drag racers I know don't want to miss out on the couple tenths an out of the box carb will miss. It ain't hype when the time slips prove it, DD
 
i would go 950 hp also, i'm using a 750 hp with annulars and 4-corner and its good, but the 950 would be better.
 
daredevil said:
Most drag racers I know don't want to miss out on the couple tenths an out of the box carb will miss. It ain't hype when the time slips prove it, DD
Click to expand...

like i said, i believe its combo dependent

Its definatly the opposite of hype when a custom carb builder jets your application wrong though....and that does happen

not downplaying it, just saying from an affordable hands on point of view, most anyone can tune a holley carb to work the way they want
 
You must log in or register to reply here.
-

Back
Top