Finally got a new carburetor

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flyfish

flyfish

C8H18+N2O = :-D
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As some of you know, I've had a carb that was "too small" for my combo for a lot of years. Well, I finally sucked it up and bought a new Holley XP 950, e85 carb. This will be replacing the 750 e85 carb that I built a few years back.

I'll be doing some testing and racing with it Friday and Saturday. There is a TNT session before the Friday race where I hope to do a back to back comparison....I'm really hoping the new carb out performs the old home built piece. The 950 feels GREAT on the street according to the but dyno...but I'll report the real numbers next week (assuming everything works as it should).

IMG_3636.JPG
 
Never had a smallblock.... ever..... that wasnt faster at the track with a bigger carb
Even that enginemasters 318 i had was .12 quicker with a 950 than it was with the better of two 750’s i tried on it. I thougt for sure it would be quicker with a 750. Even started a thread on Moparts about it pre swapping carbs around. Several small block guru’s told me the 950 would be fastest. I was wrong. It was, they were right
Must be why at enginemasters it was dyno’ed with a 950. Lol
I did have a 1025 race Demon though that ran almost identical to an 1100 pro systems dominator. It was very close. This on another motor obviously.
 
Well, if nuthin else it sure does look good. lol
 
I really hope is picks up something. I have a friend that I race with that went to a 950 on his small block Valiant and it ran the same as his 750 Demon (6.60's in the 1/8)....so I've been a little gun shy of pulling the trigger on the bigger carb, even though I'm pretty sure my car will like it.

For Fklskv, is it on my 408 (13:1, ported eddys, 264/268 cam w/ ~0.620 lift, Victor intake)
 
I wanted the list number so I could look up the specs.

That’s a big 4150 carb...... 1.600 venturi with a 1.750 throttle bore.

There have been some reported misgivings about how well that particular main body performs.

The unsolicited armchair quarterback opinion here is...... I would have used something with a smaller venturi.

Nonetheless, I hope it works well for you..... and look forward to the track report.
 
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Yes, side by side with my 750, it is a large difference in size.

It made me laugh, because the instructions said that it was dialed in from the factory to bolt on and go......The thing did not work out of the box (which I expected)....the rear needle & seat would not close, which drowned the car within 10 seconds of starting it. I removed it, cleaned it with some WD40, put it back, works fine now. The 4 corner idle screws were only open about 1/2 a turn (it needed about 1 1/2 turns).

One cool feature that my old carb didn't have is the idle air bleed (not sure of the real name for it) that is under the air filter stud. It lets big cams idle just fine without opening the throttle blades or having to drill the butterflies....its a pretty cool feature.
 
Our combos are about the same
Actually I have less compression and less cam
12.5 to 1
And 260@50 .415 lift
And I used that carb from the start
And I’ve been 6.39 a few times but mostly 6.40 @ 3000lbs
 
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Man, I wish we had E85 here.. I'll be awaiting results.
 
70aarcuda said:
according to google their is about a dozen stations selling it in reno
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there is not.. Only e85 available is special order and by the drum.

We did send in a petition to try and get the Maverik gas stations to start carrying it. But don't know if that will happen.
Sign the Petition
 
o1heavy said:
Our combos are about the same
Actually I have less compression and less cam
12.5 to 1
And 260@50 .415 lift
And I used that carb from the start
And I’ve been 6.39 a few times but mostly 6.40 @ 3000lbs
Click to expand...
Yeah, I should see some 6.40's in the fall. I would be ecstatic if I could get a 40 in the summer heat, but I'll be happy with anything quicker than the old carb. The last outing a few weeks ago it was running 6.67 in hot humid air.

Me and my car need to lose a little weight...Last time I scaled it we were 3250lbs, which is weird because not too long before that it was 3200lbs....probably just the inaccuracy of the scale, or I ate a lot of dounuts...
 
B3422w5 said:
Never had a smallblock.... ever..... that wasnt faster at the track with a bigger carb
Click to expand...

Spot on, my stock CR '71 340 Cuda went 1.8tnths quicker with an 850DP over the 750DP it came with
 
Hot Metal said:
Spot on, my stock CR '71 340 Cuda went 1.8tnths quicker with an 850DP over the 750DP it came with
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I built the 750 from 3 different carbs + a e85 conversion kit off ebay. Tuning the carb was a process that spanned the course of an entire race season, but it's about as perfect as I could get it for my car...which is why I'm not getting my hopes up too high with the first outing with the 950. It will more than likely need a hand full of days at TnT nights to get it dialed in....but I'm pretty stoked. :)
 
Quick update (because work is busy today). Due to many unforeseen circumstances, I did not have time to do testing with both carbs Friday. I ran the 950 this weekend and it ran the same as the 750 that I built (looking at previous data with very similar air)…which is good for a baseline. The AFR was 0.87 lambda at WOT which is on the lean side of max power, but still good. Will probably jet it up for the next race (this weekend). Overall, was hoping for big numbers, but was realistic knowing I tuned the crap out of my 750, so It would be hard to beat it out of the box. The 950 will probably get faster with tuning, its just going to take a little time. Eventually I will do a TnT night and do back to back runs to compare, but I will probably wait till it is a little cooler out so the starting line is not an issue.


Air was hot and humid this weekend, car was running 6.67-6.69. My tires are old…60’ not what it used to be. Had some slight traction issues, had to dial for it…went 3 rounds Saturday, lost to myself (gave the stripe back).

The race Friday was a freeking circus and a joke…and a bad joke at that. I will probably never do that race again, which is too bad because I like what the promoter is trying to do….the execution was VERY poor though. I might try it again if they can get their crap together (really long story).
 
What you got ain't a carburetor. Might as well be a siphon. THIS is a carburetor.

BIG BO.jpg
 
RustyRatRod said:
What you got ain't a carburetor. Might as well be a siphon. THIS is a carburetor.

View attachment 1715363765
Click to expand...
flyfish said:
Quick update (because work is busy today). Due to many unforeseen circumstances, I did not have time to do testing with both carbs Friday. I ran the 950 this weekend and it ran the same as the 750 that I built (looking at previous data with very similar air)…which is good for a baseline. The AFR was 0.87 lambda at WOT which is on the lean side of max power, but still good. Will probably jet it up for the next race (this weekend). Overall, was hoping for big numbers, but was realistic knowing I tuned the crap out of my 750, so It would be hard to beat it out of the box. The 950 will probably get faster with tuning, its just going to take a little time. Eventually I will do a TnT night and do back to back runs to compare, but I will probably wait till it is a little cooler out so the starting line is not an issue.


Air was hot and humid this weekend, car was running 6.67-6.69. My tires are old…60’ not what it used to be. Had some slight traction issues, had to dial for it…went 3 rounds Saturday, lost to myself (gave the stripe back).

The race Friday was a freeking circus and a joke…and a bad joke at that. I will probably never do that race again, which is too bad because I like what the promoter is trying to do….the execution was VERY poor though. I might try it again if they can get their crap together (really long story).
Click to expand...


Unless you post the Venturi diameters, the 750/950 doesn't mean a thing.

I can show you a carb with a much smaller Venturi than either carb you are talking about that will flow about the same.
 
fishmens67 said:
please show me the way, where can I find it?
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It's BLP performance. Here you go.

Alky carbs:
BXX SERIES COATED BILLET CARBURETOR ALKY BoMax Ext Black Teflon Coated Billet carburetor [4044C-BXX-A-M-D] - $2,200.00 : BLP Products

Gas carbs:
BXX SERIES COATED BILLET CARBURETOR ALKY BoMax Ext Black Teflon Coated Billet carburetor [4044C-BXX-A-M-D] - $2,200.00 : BLP Products

I think the stretched ones can flow over 3000 CFM. You just call them and tell them "how big". The stretched ones have two BIG oval barrels in the base plate. They flow like a ****. I wanna see an engine that can suck two of them down a tunnel ram.
 
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