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What's the right carb for my combo? Street/Strip
#3017185
02/20/22 07:43 PM
02/20/22 07:43 PM
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Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
Quicksilver440
OP
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OP
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Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
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Ive been away from moparts and drag racing for a long time...10 years..and trying to get my car going again. My combo was a 440, Manley H beam rods, Wiseco pistons, 10.2:1 compression on pump gas, ported Eddie heads, Holley Street Dominator, 2" headers...small hyd 242@ .050 cam and 800DP holley...9.5" converter. 4.10 Dana 60 in a 71 Challenger. Weighs about 3500 lbs with me in it.
With a little hyd cam and small 800 dp holley ran 11.47 @118. Never really got the chassis or car sorted out before I parked it.
10+ years ago I put in a larger 252@ .050 solid cam and a 850 dp and it ran a little slower the one time I had it out with the cam and carb change then life happened, more kids, etc and the car sat in the garage for more than 10 years. The 850 DP never ran as well as the old 800 DP either on the Street or strip.
Looking for a new carb recommendation...back then the 950HP seemed like the ticket for this kinda combo...what should I look at now. Holley now has more models than I can understand...950HP classic maybe?
Last edited by Quicksilver440; 02/20/22 08:42 PM.
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Re: What's the right carb for my combo? Street/Strip
[Re: Quicksilver440]
#3017210
02/20/22 09:12 PM
02/20/22 09:12 PM
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Joined: Aug 2003
Posts: 43,915
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,915
Bend,OR USA
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What size fuel line, what size pickup in the gas tank and fuel pump? I would make sure that you don't have a fuel volume supply problem at WOT only and go from there. I've built and raced B and RB motors for a long time in many different cars before finding out the stock fuel lines and pickups won't feed much above 450 HP, some versions of the stock fuel pumps won't feed 400 HP :at WOT in the 1/4 mile whiney:  Have you cleaned out the gas tank, lines and filter? Are using all new fresh fuel? If not, you should:  wrench: Murphy loves messing with us hotrodders and drag racers    Did you degree the cam or install it straight up? If straight up I would make sure it is installed properly, I seen more than one replacement cam gear be off one tooth and make the cam install retarded instead of correctly  Which makes the motors not run as good as they can when the cam is installed correctly 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: What's the right carb for my combo? Street/Strip
[Re: gregsdart]
#3017236
02/20/22 10:22 PM
02/20/22 10:22 PM
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Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
Quicksilver440
OP
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OP
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An 850 is not too big for a 440. What is the stall of your converter? Have you tried tuning the 850? Any changes, like aircleaner? Greg…converter is 9.5” dynamic that stalled about 3800 rpm. Ranit at the track without an air cleaner…but no other tuning really other than (10 years ago) adjusting idle mixture for max vacuum. Now rebuilt it after sitting and it won’t idle at all…😂
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Re: What's the right carb for my combo? Street/Strip
[Re: Quicksilver440]
#3017253
02/21/22 12:42 AM
02/21/22 12:42 AM
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Joined: Jan 2003
Posts: 31,264
Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 31,264
Oregon
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Do you want a race carb or something with a choke so you can drive it in colder weather? If you want a race carb I'd probably go with a QuckFuel 750 DP. I'm guessing your engine makes about 500 to 550 hp so a 750 carb will be adequate. For street driving a slightly smaller carb will work better than a bigger carb. If you are drag racing only then maybe buy another 850 if you want but my guess is that you'll be happier with a 750. Holley has the new Ultra XP carbs which are really nice but they are expensive. They are very good carbs though and should run great right out of the box. $1000 and they are in stock: https://www.summitracing.com/parts/hly-0-80803bkx
Last edited by AndyF; 02/21/22 12:44 AM.
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Re: What's the right carb for my combo? Street/Strip
[Re: Quicksilver440]
#3017264
02/21/22 05:33 AM
02/21/22 05:33 AM
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Joined: Jan 2003
Posts: 3,007
A shed in England
Tig
master
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master
Joined: Jan 2003
Posts: 3,007
A shed in England
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We had a 440 with all the usual, ported iron heads, torquer2, .509 cam. 10" B and M converter 3.91 gears etc. We switched the 750 d/p to a 850 d/p and dropped a solid 2 10th's (12.50's - 12.70's). We tried the usual jet, timing adjustments and just couldn't get it back. I'd sold the 750 and wished I hadn't. About a year later a friend was selling a couple of 950's he'd had on a T/R BBC. I asked if I could try one and said if I went faster I'd buy it. We slapped it on, set the idle and picked up 3 10ths off the get go (12.40's) Later that same day we ran a 12.30 and eventually, we got that combo to go 12.00's.
Go figure. Obviously I bought it but I scratched my head as to why we picked up over both the 750 and 850. I found out that the 950 wasn't really a 950cfm rated carb as it had smaller venturies than the 850, it just worked right for that combo. My experience.
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials.
9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge.
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
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Re: What's the right carb for my combo? Street/Strip
[Re: Tig]
#3017285
02/21/22 09:08 AM
02/21/22 09:08 AM
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Joined: Oct 2015
Posts: 570
UK
rb446
mopar
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mopar
Joined: Oct 2015
Posts: 570
UK
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My s/strip '71 340 Cuda with a 750DP, .484/284 hyd. cam ran well, put an 850DP on it picked up almost 2/10ths. Same carb on my stock all iron 440 with a big sft cam made 530fwhp on track, ran perfect on both my motors. Its the carb itself, set them up well and they'll run hard on anything. You should never lose time with a larger carb if you've got a perf combo on a mopar.
We ran/run an old 950HP (830cfm) on my mates mild 10:1 589ci wedge motor through muffs on track, (showed 2" hg@6000rpm on dyno so restrictive), but it runs real good and only drops around 20>25hp from the dyno numbers worked on weight/mph. They tried a 1050 Dom on the dyno and it made 1hp more, carb not set up or rubbish.
Last edited by rb446; 02/21/22 09:51 AM.
1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
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Re: What's the right carb for my combo? Street/Strip
[Re: Quicksilver440]
#3017349
02/21/22 12:49 PM
02/21/22 12:49 PM
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Joined: Dec 2021
Posts: 1,398
Loudoun County, VA
Brad_Haak
pro stock
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pro stock
Joined: Dec 2021
Posts: 1,398
Loudoun County, VA
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Rob - If I could find a link to where I've talked about this before, I would cuz this feels like I'm repeating myself (again).
The standard / traditional Holley 850 isn't "too big", but it's got a large venturi-to-throttle-bore ratio 1.56v x 1.75t and "meh" boosters that don't generate great signal.
The original 80496 "950" w/ 1.38v x 1.75t won't make more power on an engine dyno, but can run quicker & faster at the track because of better throttle response and shift recovery for some (many?) combinations. IMO, the more limited a combination is by converter speed and gear, the more likely the improvement.
I know 4 people, including myself, who swapped those two carbs at the track and saw .15 to .2 tenths and 1.5 to 2 MPH improvements with the 80496; in my case it dropped my 60-ft from 1.70 to 1.55 ET & MPH went from 11.7 at 117 to 11.5 at 119. The engine dyno showed basically no difference between them; it came out on the ET slip.
If I was buying a new carb today for a similar application, I'd try a Proform / Brawler "950" race carb w/ 1.45v x 1.75t simply because they're more affordable and more tuneable. If I stumbled across the sister "850" 1.40v version cheaply enough, maybe one of those. However, the "850" doesn't come with as good a booster as the "950" does.
2021 Challenger 6.4L Scat Pack 1320
100% stock: 1.680, 11.894 at 113.75 (DA 175 ft)
weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)
1973 Challenger 452 ci street/strip [2008]
pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
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Re: What's the right carb for my combo? Street/Strip
[Re: Brad_Haak]
#3017366
02/21/22 01:29 PM
02/21/22 01:29 PM
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Joined: Jan 2003
Posts: 18,049
S.E. Michigan
ZIPPY
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 18,049
S.E. Michigan
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I'd try a Proform / Brawler "950" race carb w/ 1.45v x 1.75t simply because they're more affordable and more tuneable. Liked that one so much I bought a second one of them for later tunnel ram use. All it needs is the transfer slot holes tapped and restrictors/jets added. Brawler (Actually not Brawler, Proform....correction below) also has a street carb marketed as an 850DP with electric choke, but the primary venturi measures out smaller than standard. Bought a main body of one of those to build up later for my C body. Was surprised to see that. It seems like a sound idea. hopefully get a chance to try it. For an 850, the BG annular booster model I had was so much more responsive than the two regular 4781s that I had, it killed them both so I sold them.
Last edited by ZIPPY; 03/01/22 01:22 PM. Reason: Edited to repair brand error
Rich H.
Esse Quam Videri
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Re: What's the right carb for my combo? Street/Strip
[Re: Quicksilver440]
#3017454
02/21/22 06:17 PM
02/21/22 06:17 PM
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Joined: Feb 2008
Posts: 452
Monrovia, So-Cal, USA
racerhog
mopar
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mopar
Joined: Feb 2008
Posts: 452
Monrovia, So-Cal, USA
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Pull the carb back apart and re-clean it and use some small parts tag wire to help clean the passages and flush/Blow the hell out of it.... That carb should work just fine...
Go have some fun at Bako... Cheers
Last edited by racerhog; 02/21/22 06:18 PM.
Bob(Cowboy)Hogan
Monrovia So-Cal
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Re: What's the right carb for my combo? Street/Strip
[Re: racerhog]
#3017459
02/21/22 06:34 PM
02/21/22 06:34 PM
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Joined: Jan 2003
Posts: 31,264
Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 31,264
Oregon
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Pull the carb back apart and re-clean it and use some small parts tag wire to help clean the passages and flush/Blow the hell out of it.... That carb should work just fine...
Go have some fun at Bako... Cheers That might work, it is at least a cheap experiment. I wouldn't be surprised that it didn't work though. I've run across a number of "bad apple" carbs over the years and no amount of cleaning or rebuilding will fix them. Some carbs just don't work right. If the OP's carb didn't work right out of the box then it could just be a bad apple. If it worked okay before clogging up with dirt then is should be easy to flush out. From what the OP said, it sounded more like it was never a good carb.
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Re: What's the right carb for my combo? Street/Strip
[Re: ZIPPY]
#3017493
02/21/22 08:04 PM
02/21/22 08:04 PM
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Joined: Dec 2004
Posts: 10,637
Rittman Ohio
fourgearsavoy
I Live Here
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I Live Here
Joined: Dec 2004
Posts: 10,637
Rittman Ohio
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I'd try a Proform / Brawler "950" race carb w/ 1.45v x 1.75t simply because they're more affordable and more tuneable. Liked that one so much I bought a second one of them for later tunnel ram use. All it needs is the transfer slot holes tapped and restrictors/jets added. Brawler also has a street carb marketed as an 850DP with electric choke, but the primary venturi measures out smaller than standard. Bought a main body of one of those to build up later for my C body. Was surprised to see that. It seems like a sound idea. hopefully get a chance to try it. For an 850, the BG annular booster model I had was so much more responsive than the two regular 4781s that I had, it killed them both so I sold them. I second the annular booster carb choice. I put the Pro-Form annular booster 1050 body together with some QF blocks and base plate and my car drives like a dream now and is super responsive with zero stumble and plenty of top end. Gus 
64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
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Re: What's the right carb for my combo? Street/Strip
[Re: AndyF]
#3019939
03/01/22 11:00 AM
03/01/22 11:00 AM
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Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
Quicksilver440
OP
I Live Here
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OP
I Live Here
Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
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Pull the carb back apart and re-clean it and use some small parts tag wire to help clean the passages and flush/Blow the hell out of it.... That carb should work just fine...
Go have some fun at Bako... Cheers That might work, it is at least a cheap experiment. I wouldn't be surprised that it didn't work though. I've run across a number of "bad apple" carbs over the years and no amount of cleaning or rebuilding will fix them. Some carbs just don't work right. If the OP's carb didn't work right out of the box then it could just be a bad apple. If it worked okay before clogging up with dirt then is should be easy to flush out. From what the OP said, it sounded more like it was never a good carb. Sorry my delayed responses guys…I was gone for some flight training and was consumed by that for the last week. Really appreciate all the info/help/responses. Andy…I think your right. It’s never been a good carb…I’ve built plenty before with good success, but this one has never been good.
Last edited by Quicksilver440; 03/01/22 11:01 AM.
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Re: What's the right carb for my combo? Street/Strip
[Re: Brad_Haak]
#3019941
03/01/22 11:07 AM
03/01/22 11:07 AM
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Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
Quicksilver440
OP
I Live Here
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OP
I Live Here
Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
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Rob - If I could find a link to where I've talked about this before, I would cuz this feels like I'm repeating myself (again).
The standard / traditional Holley 850 isn't "too big", but it's got a large venturi-to-throttle-bore ratio 1.56v x 1.75t and "meh" boosters that don't generate great signal.
The original 80496 "950" w/ 1.38v x 1.75t won't make more power on an engine dyno, but can run quicker & faster at the track because of better throttle response and shift recovery for some (many?) combinations. IMO, the more limited a combination is by converter speed and gear, the more likely the improvement.
I know 4 people, including myself, who swapped those two carbs at the track and saw .15 to .2 tenths and 1.5 to 2 MPH improvements with the 80496; in my case it dropped my 60-ft from 1.70 to 1.55 ET & MPH went from 11.7 at 117 to 11.5 at 119. The engine dyno showed basically no difference between them; it came out on the ET slip.
If I was buying a new carb today for a similar application, I'd try a Proform / Brawler "950" race carb w/ 1.45v x 1.75t simply because they're more affordable and more tuneable. If I stumbled across the sister "850" 1.40v version cheaply enough, maybe one of those. However, the "850" doesn't come with as good a booster as the "950" does. I think that’s great advice Brad…thanks. I went back and searched the archives and read some of your past posts on this topic as well. I was having trouble finding the Venturi sizes on the Brawler carbs…curious about the choked version Venturi sizes too since it seems to have most of the features of their “race” carbs.
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Re: What's the right carb for my combo? Street/Strip
[Re: ZIPPY]
#3019944
03/01/22 11:09 AM
03/01/22 11:09 AM
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Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
Quicksilver440
OP
I Live Here
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OP
I Live Here
Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
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I'd try a Proform / Brawler "950" race carb w/ 1.45v x 1.75t simply because they're more affordable and more tuneable. Liked that one so much I bought a second one of them for later tunnel ram use. All it needs is the transfer slot holes tapped and restrictors/jets added. Brawler also has a street carb marketed as an 850DP with electric choke, but the primary venturi measures out smaller than standard. Bought a main body of one of those to build up later for my C body. Was surprised to see that. It seems like a sound idea. hopefully get a chance to try it. For an 850, the BG annular booster model I had was so much more responsive than the two regular 4781s that I had, it killed them both so I sold them. Zippy…super interested in a electric choke carb with smaller venturis…seems like a great idea. I’ll check that out!
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Re: What's the right carb for my combo? Street/Strip
[Re: Quicksilver440]
#3019985
03/01/22 01:13 PM
03/01/22 01:13 PM
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Joined: Jan 2003
Posts: 18,049
S.E. Michigan
ZIPPY
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 18,049
S.E. Michigan
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I'd try a Proform / Brawler "950" race carb w/ 1.45v x 1.75t simply because they're more affordable and more tuneable. Liked that one so much I bought a second one of them for later tunnel ram use. All it needs is the transfer slot holes tapped and restrictors/jets added. Brawler also has a street carb marketed as an 850DP with electric choke, but the primary venturi measures out smaller than standard. Bought a main body of one of those to build up later for my C body. Was surprised to see that. It seems like a sound idea. hopefully get a chance to try it. For an 850, the BG annular booster model I had was so much more responsive than the two regular 4781s that I had, it killed them both so I sold them. Zippy…super interested in a electric choke carb with smaller venturis…seems like a great idea. I’ll check that out! I must apologize, I didn't remember the brand correctly. Your reply made me go check. I thought it was a QFT Brawler, but it is actually a QFT Proform. Pics below. I'm coming up with 1.465(P) and 1.554(S) using basic dividers and a dial caliper. Proform doesn't advertise the spec (that I have been able to easily find,anyway), whereas Brawler advertises 1.570 P/S. If the Brawler marketing is correct then the carbs are definitely not the same in spite of how badly I might mix them up. https://www.holley.com/products/fuel_systems/carburetors/street/parts/BR-67214https://www.proformparts.com/produc...odel-850-cfm-mechanical-secondaries-type
Rich H.
Esse Quam Videri
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Re: What's the right carb for my combo? Street/Strip
[Re: lewtot184]
#3020136
03/02/22 01:25 AM
03/02/22 01:25 AM
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Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
Quicksilver440
OP
I Live Here
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OP
I Live Here
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Central Valley, CA.
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a lot of good single carb info here, but i have to wonder if the manifold is best for the combo? it could be fine and i know it's had some good press but what "IF"? i don't care for single carb stuff much anymore, especially when cost is factored in. i'd open the door to a lot of options. the worst that looking could do is send you back to what you have. Manifold is a Holley Street Dominator…ran really well with the 800 DP I used to have. I also have a new Victor that I’ve never ran…but I bought it to run with Fuel injection that I never ended up finishing.
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