Best CFM carb for a 416????

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swinger340

swinger340

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Decided to build a 10.2:1 416 with a forged assembly. Eddy heads flow 275/200 @ .600 My cam will probably be a .555 solid flat tappit cam. Going in a 3100 lb car with 3:91s and a 3500 stall. Gasket matched Performer RPM air gap. Wondering if an 850 will be fine or should I get a 950? Also curious if a carb spacer will gain power and if so which one. Once i get it together I have some free dyno pulls at a buddys shop some weekend. He is a chevy nut so I want to show him what a small mopar can do. He is the same guy that said 350HP on my 340 that pulled 428. He is guessing 450 on the 416. Im shooting for 500 or a touch better
 
Maybe a voodoo 60434 solid roller will make some good power. .600/.600 255/263 @ .050 110/106 Not sure if it is worth the $750 for what power I will gain. Could shave a little off the heads as well to get the compression up to 10.5:1
 
I like the 870 Avengers for a street car or the HP950 for a track car with a 4" stroke engine.
 
The 950 has a smaller venturi than the 850, so it would make sense to say the 950 while flowing more...would give better throttle response.
So the 950 is what I recommend.
 
Actually,the answer lies in OU812's latest 408 thread.Explains the carb,and even better,why.
 
In lamens , the smaller venturi 'though tapered' adds more air speed at the booster, mixes fuel better and at lower speeds. As for any particular model of 950 being calibrated leaner or richer...that's a different story and in the tunning. I always like tuning towards the leaner side on my street stuff, crisper response all over...maybe in some cases the peak is down a hair, maybe not...
Have the op pay for a dyno test in order to prove this or that, otherwise school yourself on tuning and trial error time is where ull find out.
And the testing in that thread is in the high desert dude..leaner is where u go, hense corrected number based on denser air and other things.
Don't have time for a pissing match, people can latch onto whatever they want. Good luck
 
I'll second 1Wild there... Also - the Ultra line that Brian got most power from - It has no provision for a choke (similar to the HP950..) and no provision for factory throttle or kickdown linkages... So While reading about a cool dyno session is cool, sometimes mimicking the package might no be what you're looking for... That's why I use the Avenger series a lot - they are basically a bolt on and the normal adaptors and works great on the longer stroke small block.
 
swinger340 said:
Decided to build a 10.2:1 416 with a forged assembly. Eddy heads flow 275/200 @ .600 My cam will probably be a .555 solid flat tappit cam. Going in a 3100 lb car with 3:91s and a 3500 stall. Gasket matched Performer RPM air gap. Wondering if an 850 will be fine or should I get a 950? Also curious if a carb spacer will gain power and if so which one. Once i get it together I have some free dyno pulls at a buddys shop some weekend. He is a chevy nut so I want to show him what a small mopar can do. He is the same guy that said 350HP on my 340 that pulled 428. He is guessing 450 on the 416. Im shooting for 500 or a touch better
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The 950 will be 10HP better than a 750DP. If the 10HP is worth the extra 300.00 then go for it...if not the 750DP is a great carb when put on top of a rpm airgap intake and a 1" open spacer.
I've not tried an 850DP yet inplace of the 750, but it will be down on fuel mileage and throttle response some...not a big deal as throttle response doesn't dictate actual power made. It just sounds cool in Park!!

And to be clear...our shop is the Low Desert, and actually sits 8ft. below sea level.
 
We live in the Low Desert... :) Right around sea level... just fricken hot in the summer time.

The 950hp really flows around 830cfm. The 950 claim is marketing. The UltraHP alum bodies do flow in the 900's.

I will say that the 950hp usually has a good wide open fuel curve in them. The cruise metering is REALLY fat and needs some work to get right.
 
I already own a 750 barry grant and a Holley 850HP. A buddy of mine will swap me a Proform 950 for the 750 barry grant, but im kinda partial to that carb. Where may I want to start on jet sizes? If I recall correctly the Barry Grant had 72/84 when it was on the 340
 
ou812 said:
I've not tried an 850DP yet inplace of the 750, but it will be down on fuel mileage and throttle response some...not a big deal as throttle response doesn't dictate actual power made. It just sounds cool in Park!!
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I'm not sure about a 4150 series 850 (DP). The VS 870 Avenger gets over 17 on a street 422 w/3.23s in a heavy E body and there is no throttle response issues. Just lots of traction issues.

I'd say any dyno info from that 408 build is almost useless for the engines most here are building. Not to mention that once that engine's in a car racing the differences you make of note won't mean **** and it will be back to the drawing board for baseline tuning.
 
moper said:
I'm not sure about a 4150 series 850 (DP). The VS 870 Avenger gets over 17 on a street 422 w/3.23s in a heavy E body and there is no throttle response issues. Just lots of traction issues.

I'd say any dyno info from that 408 build is almost useless for the engines most here are building. Not to mention that once that engine's in a car racing the differences you make of note won't mean **** and it will be back to the drawing board for baseline tuning.
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Can you be more specific about the differences I note that won't mean ****?
 
I have a 950hp off my 340 for sale cheap in the parts section:D
 
ou812 said:
Can you be more specific about the differences I note that won't mean ****?
Click to expand...

Are you asserting that there is no noted difference between the 408 you dyno'd and the 416 of the OP that might make a different carburetor a better choice?
 
swinger340 said:
Maybe a voodoo 60434 solid roller will make some good power. .600/.600 255/263 @ .050 110/106 Not sure if it is worth the $750 for what power I will gain. Could shave a little off the heads as well to get the compression up to 10.5:1
Click to expand...

I am in the process of replacing my PP 508 hyd cam with the Voodoo 60434. It makes some serious power - about 50HP more than what I got with the hyd cam. Torque is way low. Here is a build MRL did with that cam... I am basically duplicating it on my 416.

http://www.forabodiesonly.com/mopar/showthread.php?p=1969460210#post1969460210
 
wow, I can't believe the people jumping all over someone who is actually willing to post some numbers and results from a test he is doing on an engine (ALOT of shops won't do that unless they are sponsoring a site or getting some direct profit from it)...Nowhere in his post did he say that what he did is the only thing to work, or how it should be done on all builds- he was just noting changes he made and what picked up or made the most power on the DYNO! No mention of the track, and if you really think a builder doesn't know that the track is where the real tuning occurs, then your are a bunch of tools...Again, read DYNO TEST TO SHOW DIFFERENT PARTS CHANGING POWER LEVELS AND PEAKS
 
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