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What's the right carb for my combo? Street/Strip #3017185
02/20/22 08:43 PM
02/20/22 08:43 PM
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Central Valley, CA.
Quicksilver440 Offline OP
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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 09:42 PM.
Re: What's the right carb for my combo? Street/Strip [Re: Quicksilver440] #3017210
02/20/22 10:12 PM
02/20/22 10:12 PM
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Cab_Burge Offline
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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: twocents
Have you cleaned out the gas tank, lines and filter? Are using all new fresh fuel?
If not, you should: scope wrench:
Murphy loves messing with us hotrodders and drag racers rant work shruggy
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 puke
Which makes the motors not run as good as they can when the cam is installed correctly whiney


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: What's the right carb for my combo? Street/Strip [Re: Quicksilver440] #3017216
02/20/22 10:27 PM
02/20/22 10:27 PM
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Posts: 9,527
Frostbitefalls MN (Rocky&Bullw...
gregsdart Offline
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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?


8.77 153 mph best, 3055 lbs 528 indy 440-1 alky
Re: What's the right carb for my combo? Street/Strip [Re: Cab_Burge] #3017233
02/20/22 11:19 PM
02/20/22 11:19 PM
Joined: Jan 2003
Posts: 10,765
Central Valley, CA.
Quicksilver440 Offline OP
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Cab….a custom hot rod city aluminum fuel tank with fuel sump. AN -6 Teflon fuel line to Aeromotive SS 140 gph pump. AN -6 Teflon to Mallory fuel pressure regulator and AN -6 Teflon to carb.

850 just never seemed as responsive as the 800DP….especially on the street.

After 10 years of mostly sitting…I decided to try and make March Meet (Bakersfield/Famoso)…so after finding that my needle seats where stuck open I rebuilt the carb last weekend and now I can’t get it to idle at all (Doesn’t seem to run on the idle circuit) so was considering a new carb since I never felt I liked this carb anyways….but it did run ok previously (before sitting).

Re: What's the right carb for my combo? Street/Strip [Re: gregsdart] #3017236
02/20/22 11:22 PM
02/20/22 11:22 PM
Joined: Jan 2003
Posts: 10,765
Central Valley, CA.
Quicksilver440 Offline OP
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Originally Posted by gregsdart
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…😂

Re: What's the right carb for my combo? Street/Strip [Re: Quicksilver440] #3017253
02/21/22 01:42 AM
02/21/22 01:42 AM
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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 01:44 AM.
Re: What's the right carb for my combo? Street/Strip [Re: Quicksilver440] #3017261
02/21/22 03:13 AM
02/21/22 03:13 AM
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Bend,OR USA
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You have a PM on this scope up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: What's the right carb for my combo? Street/Strip [Re: Quicksilver440] #3017264
02/21/22 06:33 AM
02/21/22 06:33 AM
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A shed in England
Tig Offline
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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 and 145.9 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 with our old mule 580 wedge
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
Re: What's the right carb for my combo? Street/Strip [Re: Tig] #3017285
02/21/22 10:08 AM
02/21/22 10:08 AM
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UK
rb446 Offline
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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 10:51 AM.

1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: What's the right carb for my combo? Street/Strip [Re: Quicksilver440] #3017349
02/21/22 01:49 PM
02/21/22 01:49 PM
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Loudoun County, VA
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Brad_Haak Offline
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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.

Re: What's the right carb for my combo? Street/Strip [Re: Brad_Haak] #3017366
02/21/22 02:29 PM
02/21/22 02:29 PM
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S.E. Michigan
ZIPPY Offline
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Originally Posted by Brad_Haak
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 02:22 PM. Reason: Edited to repair brand error

Rich H.





Re: What's the right carb for my combo? Street/Strip [Re: Quicksilver440] #3017454
02/21/22 07:17 PM
02/21/22 07:17 PM
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Monrovia, So-Cal, USA
racerhog Offline
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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 07:18 PM.

Bob(Cowboy)Hogan
Monrovia So-Cal
Re: What's the right carb for my combo? Street/Strip [Re: racerhog] #3017459
02/21/22 07:34 PM
02/21/22 07:34 PM
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Originally Posted by racerhog
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.

Re: What's the right carb for my combo? Street/Strip [Re: ZIPPY] #3017493
02/21/22 09:04 PM
02/21/22 09:04 PM
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Rittman Ohio
fourgearsavoy Offline
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Originally Posted by ZIPPY
Originally Posted by Brad_Haak
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 beer


64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
Re: What's the right carb for my combo? Street/Strip [Re: AndyF] #3019939
03/01/22 12:00 PM
03/01/22 12:00 PM
Joined: Jan 2003
Posts: 10,765
Central Valley, CA.
Quicksilver440 Offline OP
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Quicksilver440  Offline OP
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Originally Posted by AndyF
Originally Posted by racerhog
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 12:01 PM.
Re: What's the right carb for my combo? Street/Strip [Re: Brad_Haak] #3019941
03/01/22 12:07 PM
03/01/22 12:07 PM
Joined: Jan 2003
Posts: 10,765
Central Valley, CA.
Quicksilver440 Offline OP
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Quicksilver440  Offline OP
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Originally Posted by Brad_Haak
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.

Re: What's the right carb for my combo? Street/Strip [Re: ZIPPY] #3019944
03/01/22 12:09 PM
03/01/22 12:09 PM
Joined: Jan 2003
Posts: 10,765
Central Valley, CA.
Quicksilver440 Offline OP
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Quicksilver440  Offline OP
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Originally Posted by ZIPPY
Originally Posted by Brad_Haak
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!

Re: What's the right carb for my combo? Street/Strip [Re: Quicksilver440] #3019967
03/01/22 01:09 PM
03/01/22 01:09 PM
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usa
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lewtot184 Offline
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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.

Re: What's the right carb for my combo? Street/Strip [Re: Quicksilver440] #3019985
03/01/22 02:13 PM
03/01/22 02:13 PM
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Posts: 17,268
S.E. Michigan
ZIPPY Offline
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Originally Posted by Quicksilver440
Originally Posted by ZIPPY
Originally Posted by Brad_Haak
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-67214
https://www.proformparts.com/produc...odel-850-cfm-mechanical-secondaries-type













252A3DC5-73E0-43E2-AFD5-A34888D42FC5.jpegF2F295AB-EB00-40E7-945E-6679F3150B4C.jpeg7BE135C0-B465-4FDC-87EF-4F7470438CA1.jpeg

Rich H.





Re: What's the right carb for my combo? Street/Strip [Re: lewtot184] #3020136
03/02/22 02:25 AM
03/02/22 02:25 AM
Joined: Jan 2003
Posts: 10,765
Central Valley, CA.
Quicksilver440 Offline OP
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Quicksilver440  Offline OP
I Live Here

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Central Valley, CA.
Originally Posted by lewtot184
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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