500 stroker carb selection

[Nathan Barry]

looking to buy a new carburetor for my 500 CI stroker and looking for some input from you guys,

currently has a 850 holley double pumper on it and these are the engine specs

500 Ci stroker :
eagle crank
edelbrocker torker II intake
edelbrock e street aluminum heads
9.5:1 compression
comp cam
running about 530 HP / 610 FT/LBS

wanting to stay with holley , this current carb works good but it is borrowed and im just wondering if i should buy the same one or somthing different

 

[Cojohnso1]

According to Holley selector?
https://www.holley.com/retailer/carbselector/

Holley classic HP 950. 0-80496-1

Assuming mechanical secondaries and no choke.

 

[Xp29h]

I’ve got a 512 stroker and similar set up.. I bought a Holley 950 off a member here. I felt it was a little too big. Dropped to an 850 and no complaints. Goes very well!

if you’re looking for a very good used Holley 950, let me know.. it’s just sitting here..

 

[Cojohnso1]

I have a 1050 HP metered for E-85 on a more aggressive build 451. I too believe a little big. My 850 DP on race gas works as well. (I know E-85 to Race gas is not apples to apples.)

Car runs very close to same E.T. A little higher MPH with the bigger carb. This was predicted. Smaller carb a little quicker 60' Bigger carb on top end. But it's very little difference.

 

[hunt2elk]

I run Quick Fuel mechanical sec. Q-850's on both my big block strokers. I really like them.

 

[493 Mike]

I would recommend a vacuum secondary model. Double pumpers wash a little too much oil off the cylinder walls-increasing ring/wall wear.
Mike

 

[BSB67]

I have used both the 850 DP (4781) and a "950" Holley based carb on my street 508.

You'll need to do a little homework, as not all 950s are the same, nor do they necessarily flow 950 cfm. Why they treat the "950" different than all the other carbs is a mystery to me. My "950" has small venturies - 1.390". You can get "950s" with 1.375" to 1.590" venturies, with a bunch inbetween, and their air flow ranges from about 830 to 1000 cfm.

In my opinion, the smaller venturi 950 can make a real good street carb for a milder application with taller gears and heavier car. My analogy for the small venturi 950 is that it drives like a 750, but performs like a 850.

On my car, they both drive perfectly fine. I bolted on the used 850 after I rebuilt it and did not have to do anything to it, it ran fine. I did some main jet size tweeking to the 850 at the track, but that's it. The 950 took a little work. It was fat at idle and transition, but nothing crazy. It needed track tweeking as well.

The track results were pretty consistant in that the 950 seemed a bit better everywhere at the track and made a bit more power, when correcting all of the testing results to standard conditions. The 0.15 - 0.20 seceond and 1.5 - 2 mph improvement with the 950 would be un-noticed on the street.

 

[Rubberduck]

For my 505 cui. I opted for Fi Tech:
https://fitechefi.com/product/go-efi-4-600hp-system/



Mario

 

[Lefty71]

If you were drag racing, I would go with a 1050 DOMINATOR, preferably with an adapter onto a square bore manifold....... but we dont know the intended use.... If you are staying on the street with this, then I would use a smaller carb (but no smaller than what you have), and as Mike says, certainly nothing wrong with vaccuum secondaries to monitor the needed airflow at any givin time.

 

[68 HEMI GTS]

Probably a 1000 cfm 4150 would be my choice. I’ve ran all kinds of different set ups on my street 512. Mines a bit healthier so I ended up liking to run dominators on it. I had a 1050/4150 annular carb on it that was an excellent street carb.

 

[Aron Gleason]

Look up Dominic thumper on Facebook. He's the go to carburetor guru.

 

[383man]

I have been running the Holley 850 DP on my 493 for 10 years. Its a street car that I race about once or twice a year. I will say I had to jet up a good bit from what my old 440 wanted as my 493 wanted fuel. But this 850 DP has worked awesome all these years. I have only tweaked it a tad so that it cruises the streets nice at part throttle and works good at the track. It has great drivability with the 850 as the Double pumper carbs work great on strokers. I did bolt a Holley 950 HP carb on it about two years ago and ran the same 10.70's but it ran almost 126 mph as it picked up a little mph. I actually did some work on the 950 and just put it back on the car as I want to try it again in cooler air. It also drives and runs great. I hope to get back to the track this year and see how it does. But honestly the car worked so nice with the 850 DP as its a great carb for my 493 that makes around 600 flywheel hp. The 850 is a great all around street/strip carb for a 500 to 600 hp stroker. Ron

 

[beanhead]

I would recommend a vacuum secondary model. Double pumpers wash a little too much oil off the cylinder walls-increasing ring/wall wear.
Mike

 

[493 Mike]

What is funny about my statement?
Mike

 

[68 HEMI GTS]

What is funny about my statement?
Mike

I think he’s poking at the inaccuracy of your statement. Any carb can be out of tune and wash the rings. I think double pumpers tend to naturally run on that side out of the box. With proper calibrations though they can run just a clean and any other carb.

 

[493 Mike]

I think he’s poking at the inaccuracy of your statement. Any carb can be out of tune and wash the rings. I think double pumpers tend to naturally run on that side out of the box. With proper calibrations though they can run just a clean and any other carb.

I tend to agree with Rick Ehrenberg at Mopar Action on the extra fuel washing the cylinder walls VS a vacuum secondary carb.
Mike

 

[383man]

I tend to agree with Rick Ehrenberg at Mopar Action on the extra fuel washing the cylinder walls VS a vacuum secondary carb.
Mike

I have run Double Pumpers since the 70's on my cars and have never had a problem of washing the cylinders and have never blown an eng. The only extra fuel is the secondary pump and thats because without and air valve on a mech secondary carb it needs the secondary accel pump or the car would fall on its face when the secondaries open up. Even four barrel carbs that are mech secondaries with an air valve and no secondary pump like the Thermoquad or Quadrajet pull more fuel as the secondary air valve opens when floored. They even have an extra fuel hole that pulls even more fuel as the air valve passes the hole in the airhorn. The Quadrajet even calls that hole an accel pump but it does not pump fuel it draws fuel out of the hole as the air valve opens up. I respect Rick from MA but disagree 100% on that comment as my own use of DP proves it wrong. Ron

 

[68 HEMI GTS]

Here’s a prime example of a 1050/4500 mechanical secondary dominator not washing the rings... lol

https://youtube.com/shorts/Au8o2RiGdKs?feature=share

 

[Cojohnso1]

I just looked at a project car for purchase. '67 Belvedere. 511 stroker. TF heads on pump gas. From a single 950 HP carb. 686 HP at 6200 RPM. Motor only has dyno pull. We quick vid below.