#1  
Old 11-03-2023, 10:20 PM
Johnny406's Avatar
Johnny406 Johnny406 is offline
Ultimate Warrior
 
Join Date: Jan 2006
Location: Colorado Springs, CO
Posts: 2,868
Default 4150 over 4500 for a footbrake car?

I was recently talking with a gentleman about my Holley Gen III 950CFM Dominator (2 circuit) carb. It was a interesting conversation and he stated that a 4150 of the appropriate size will outperform a 4500 of the same size on a footbrake car but the advantage goes over to the 4500 if the car is on a transbrake.

I'm smart enough to know that I don't know on that one...

Is that a logical conclusion? I was thinking of having my Doninator carb converted to E-85 for the higher reving/higher compression 433 that I am building to replace the 463 that I've been running t=for the past 13 years. Would I be better off selling my Dominator and 4500 Northwind and buying a new 4150 setup? I will always be a no-box/footbrake racer.

__________________
Johnny US Army Retired
1978 T/A 463 Pontiac, KRE 74cc 292CFM D-ports, Lunati VooDoo, V-max lifters, TKII, ATM 850 E85 carb, TCI TH-350 race tranny, 3600 converter 3.73 12 bolt 11.63@116.68mph
1981 T/A 4-speed 406 Pontiac, Merrick ported 6X heads, Comp 270S cam, Crosswind intake 750 Street Demon, 3.42 30 spline Eaton posi street car.
1980 Formula 350 Pontiac back burner project
1972 LeMans 350 Pontiac
  #2  
Old 11-03-2023, 10:38 PM
PAUL K's Avatar
PAUL K PAUL K is offline
Ultimate Warrior
 
Join Date: Feb 2004
Location: Sugar Grove IL USA
Posts: 6,255
Default

Depends on the combination. A smaller carburetor will usually be more responsive down low and can 60ft better than a carburetor that is to big... But an engine the truly needs a 4500 and is set up properly will drag the smaller carburetor down the track nine times out of ten.

__________________
Go fast, see Elvis!
www.facebook.com/PaulKnippensMuscleMotors
The Following 2 Users Say Thank You to PAUL K For This Useful Post:
  #3  
Old 11-04-2023, 06:26 AM
steve25's Avatar
steve25 steve25 is online now
Ultimate Warrior
 
Join Date: May 2008
Location: Westchester NY
Posts: 14,536
Default

A bigger detail to me you need to consider in all this that you have not spoke of is your converters stated 3600 stall speed and where your new smaller stroke motor is going to make peak Tq.

You have posted nothing about your new motors cam.

__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!

1) 1940s 100% silver 4 cup tea server set.

Two dry rotted 14 x 10 Micky Thompson slicks.

1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.

Education is what your left with once you forget things!
  #4  
Old 11-04-2023, 06:36 AM
badgto's Avatar
badgto badgto is offline
Senior Chief
 
Join Date: Jul 2007
Location: broadwell,il.
Posts: 270
Default

I ran my 455 stock 067 heads backup motor this year bracket racing. I ran 3 different carbs. First one was my high dollar 1200 cfm 4500 base with times in the 7.30-7.20s @ 94. 60' was 1.53 Depending on weather. Very inconsistent. 2nd one was a 850 base ran 7.20', s @ 92 mph. limited run time on it. But noticeable down power difference in 60' Last carb was a 1050 4500 base that ran the best. 60 ' was 1.48 7.02 @ 96 mph

The Following User Says Thank You to badgto For This Useful Post:
  #5  
Old 11-04-2023, 09:30 AM
Johnny406's Avatar
Johnny406 Johnny406 is offline
Ultimate Warrior
 
Join Date: Jan 2006
Location: Colorado Springs, CO
Posts: 2,868
Default

Quote:
Originally Posted by steve25 View Post
A bigger detail to me you need to consider in all this that you have not spoke of is your converters stated 3600 stall speed and where your new smaller stroke motor is going to make peak Tq.

You have posted nothing about your new motors cam.
Good morning, I was asking in more of a general way than specific as I never heard that logic before.

As for the actual build, if I can swing the money after all the block machine work (splayed 4 bolt caps, studs, bore and hone with a torque plate etc) I plan on using a solid roller Paul K sold me. If not, I'll be using this nitrous grind Schneider SFT cam. I'm generally a 1/4 mile bracket racer but we do have a 1/8th mile no-prep series I like to do with the bottle.

Crank is my new Molnar forged 4" stroke with Molnar rods. Attached are the pistons I'm going to use and I do have a 4400 converter. I expect to need to change up to a 4:10 gear to get a little more wheel speed.
Attached Thumbnails
Click image for larger version

Name:	Scan_20171026 (2).jpg
Views:	52
Size:	69.9 KB
ID:	622778   Click image for larger version

Name:	428 Dome piston specs.jpg
Views:	49
Size:	83.6 KB
ID:	622779  

__________________
Johnny US Army Retired
1978 T/A 463 Pontiac, KRE 74cc 292CFM D-ports, Lunati VooDoo, V-max lifters, TKII, ATM 850 E85 carb, TCI TH-350 race tranny, 3600 converter 3.73 12 bolt 11.63@116.68mph
1981 T/A 4-speed 406 Pontiac, Merrick ported 6X heads, Comp 270S cam, Crosswind intake 750 Street Demon, 3.42 30 spline Eaton posi street car.
1980 Formula 350 Pontiac back burner project
1972 LeMans 350 Pontiac
  #6  
Old 11-04-2023, 03:02 PM
Dragncar Dragncar is offline
Ultimate Warrior
 
Join Date: Mar 2004
Location: Humbolt County California
Posts: 8,267
Default

Its bracket racing, most of the time you are better off running a little smaller carb than one that would make maximum power for the sake of actually trying to win races.
Usually a good 4150 will be more consistent than a 4500 and get the typical heavy bracket car out of the hole quicker.
Every time I tried a 4500 it was harder to win bracket races.
The track and a dyno are 2 very different tings.

The Following User Says Thank You to Dragncar For This Useful Post:
  #7  
Old 11-04-2023, 03:23 PM
Johnny406's Avatar
Johnny406 Johnny406 is offline
Ultimate Warrior
 
Join Date: Jan 2006
Location: Colorado Springs, CO
Posts: 2,868
Default

Quote:
Originally Posted by Dragncar View Post
Its bracket racing, most of the time you are better off running a little smaller carb than one that would make maximum power for the sake of actually trying to win races.
Usually a good 4150 will be more consistent than a 4500 and get the typical heavy bracket car out of the hole quicker.
Every time I tried a 4500 it was harder to win bracket races.
The track and a dyno are 2 very different tings.
Thank you, my ATM E-85 850 is super consistent, I won a Wally index racing last year with it. The heads up racing is just for fun, I'm always outgunned though I tend to surprise and take out a heavy hitter or two every race...

My current motor, in my opinion/observations, is too RPM limited for the 4500 Northwind. The car picked up with the port matched RPM, TKII and very ported by Greg Merrick HSD. I'm leaning on selling both the 4500 Northwind and the 950 Gen III Dominator and use the funds to buy a new 950 ATM E85 carb and use the rest of the proceeds towards building the new motor.

__________________
Johnny US Army Retired
1978 T/A 463 Pontiac, KRE 74cc 292CFM D-ports, Lunati VooDoo, V-max lifters, TKII, ATM 850 E85 carb, TCI TH-350 race tranny, 3600 converter 3.73 12 bolt 11.63@116.68mph
1981 T/A 4-speed 406 Pontiac, Merrick ported 6X heads, Comp 270S cam, Crosswind intake 750 Street Demon, 3.42 30 spline Eaton posi street car.
1980 Formula 350 Pontiac back burner project
1972 LeMans 350 Pontiac
  #8  
Old 11-05-2023, 12:46 PM
chuckies76ta's Avatar
chuckies76ta chuckies76ta is offline
Ultimate Warrior
 
Join Date: Jun 2004
Location: Canada
Posts: 3,055
Default

Quote:
Originally Posted by Johnny406 View Post
I was recently talking with a gentleman about my Holley Gen III 950CFM Dominator (2 circuit) carb. It was a interesting conversation and he stated that a 4150 of the appropriate size will outperform a 4500 of the same size on a footbrake car but the advantage goes over to the 4500 if the car is on a transbrake.

I have both of these Northwind intakes. 4150 and 4500. Both are port matched to the E-heads by SD.. I've tried the 4150 on our engine this summer and it lost et and mph but not by much. Were running a 1050 Dominator on the engine. The difficulty is that this was done during different days, temp and track prep. The only difference that I know for sure is, we had out best 60 ft with the 4500 intake. This is on a 505 cu in engine, and using foot braking off the line. So, I'm not sure I would agree with the statement your friend made. Trans brake is a whole different thing in that it allows the rpm to increase with no load on the engine as compared to foot braking. It would be best for you to do a comparison when your ready to track run and then you can make a more informed decision. And then update us.

__________________
68 Firebird. IA2 block, 505 cu in, E-head, Solid roller 3650 weight. Reid TH400 4:11 gear. 29" slick.
Best so far 10.12@133 mph. 1.43 60 ft.
76 Trans am, TKX .81 o/d, 3.73 Moser rearend,
468 with KRE D-ports, Doug headers, 3" Exh.
  #9  
Old 11-05-2023, 01:27 PM
PAUL K's Avatar
PAUL K PAUL K is offline
Ultimate Warrior
 
Join Date: Feb 2004
Location: Sugar Grove IL USA
Posts: 6,255
Default

It takes quite a bit of engine for a 4" stroke factory block combo to want a 4500 style carburetor. I posted a video of my car running one of my favorite all around 446 engines. The 4500 never helped the combo. I tried several 4150's and the fastest was one of ours that flowed around 1000 cfm and ran 10.50's NA. The smaller one I tested this day was a custom deal the carb builder was sure would help. It slowed down noticeably over the bigger carb.... Some of this might change on a lighter car, mine is definetly on the heavy side.


https://fb.watch/o7xUa0KozN/?mibextid=9R9pXO

__________________
Go fast, see Elvis!
www.facebook.com/PaulKnippensMuscleMotors
  #10  
Old 11-05-2023, 04:57 PM
Steve C. Steve C. is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Liberty Hill, Tx. (Austin)
Posts: 10,365
Default

Back-to-back track test in 2002 with my 4.125 stroke / 450 cid N/A combo.
97-98 degrees / 50% humidity / 29.25-29.40 pressure

Victor intake w/ PRC HP950 carb = 10.755 at 125.48 mph / 1.589 60-ft
Victor intake w/ 8896HP Dominator = 10.685 at 126.61 / 1.578 60-ft

Prior to the above track testing we used a Brad Urban modified 750 carburetor on the dyno.
The custom PRC carb was purchased later and used in the run above.

On the engine dyno the engine made about 15-20 more HP with the Victor/8896HP Dominator set up over a Brad Urban carb/Victor set up.
With the Brad Urban carb it made 680 hp at 6800 rpm. We used a 1/2" open spacer on the Victor intake.



.

__________________
'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 )
Old information here:
http://www.hotrod.com/articles/0712p...tiac-trans-am/

Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine)
5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension
https://www.youtube.com/watch?v=qDoJnIP3HgE

Last edited by Steve C.; 11-05-2023 at 05:16 PM.
The Following User Says Thank You to Steve C. For This Useful Post:
  #11  
Old 11-05-2023, 06:34 PM
Dragncar Dragncar is offline
Ultimate Warrior
 
Join Date: Mar 2004
Location: Humbolt County California
Posts: 8,267
Default

Quote:
Originally Posted by Johnny406 View Post
Thank you, my ATM E-85 850 is super consistent, I won a Wally index racing last year with it. The heads up racing is just for fun, I'm always outgunned though I tend to surprise and take out a heavy hitter or two every race...

My current motor, in my opinion/observations, is too RPM limited for the 4500 Northwind. The car picked up with the port matched RPM, TKII and very ported by Greg Merrick HSD. I'm leaning on selling both the 4500 Northwind and the 950 Gen III Dominator and use the funds to buy a new 950 ATM E85 carb and use the rest of the proceeds towards building the new motor.
Its the beauty of bracket races. When I won my 2nd Wally I took out this guy with a big money bracket car on both Saturday and Sunday. He seemed happy when he drew me on the opening round Saturday because my car looks like junk.
Those are the best guys to take out.

You new carb, might want to give these guys a call.
http://www.performancecarb.com/

They now almost exclusively sell all billet USA made carbs. Holley have been made in CHINA for awhile now and the quality control went down far enough for them to look for something else.
Go to the site and click on Drag Race Carbs and scroll down and you will see some pics of the billet carbs. Up to 1200cfm 4150 carbs . They are honest and give free advice. Into E85 big time.
Will straight up tell you that 1200cfm 4150 does not make quite the power of a 1200cfm 4500 carb. But customers luv them. They get a really strong signal. The boosters are lower in the venturi than a cast Holley.

  #12  
Old 11-05-2023, 06:54 PM
BILL BOWMAN1's Avatar
BILL BOWMAN1 BILL BOWMAN1 is online now
Ultimate Warrior
 
Join Date: Aug 2005
Location: Bear, Delaware
Posts: 1,545
Default

Never a bracket racer, but all my motors always picked up when I switched to a dominator.

__________________
LIFT HEAVY, LIFE IS TOO SHORT TO BE SMALL!
  #13  
Old 11-07-2023, 11:36 PM
CraigG.'s Avatar
CraigG. CraigG. is offline
Chief Ponti-yacker
 
Join Date: Jul 2004
Location: Iowa
Posts: 900
Default

I would vote for a 4150 for a foot brake consistency from track to track and weather changes - I run and love E-85 it tends to be slightly less throttle responsive than gas. 4500 for all out power - 4150 for consistency.
Mark Sullens for carb building.

  #14  
Old 11-09-2023, 02:45 PM
Skip Fix's Avatar
Skip Fix Skip Fix is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Katy,TX USA
Posts: 20,499
Default

You can get a 4150 baseplate that also fits 4500 manifolds.

__________________
Skip Fix
1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever!
1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand
1965 GTO 4 barrel 3 speed project
2004 GTO Pulse Red stock motor computer tune 13.43@103.4
1964 Impala SS 409/470ci 600 HP stroker project
1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs
  #15  
Old 11-09-2023, 08:49 PM
PAUL K's Avatar
PAUL K PAUL K is offline
Ultimate Warrior
 
Join Date: Feb 2004
Location: Sugar Grove IL USA
Posts: 6,255
Default

You can also modify an existing 4150 baseplate to work on a 4500 manifold.

__________________
Go fast, see Elvis!
www.facebook.com/PaulKnippensMuscleMotors
  #16  
Old 11-10-2023, 03:58 PM
chuckies76ta's Avatar
chuckies76ta chuckies76ta is offline
Ultimate Warrior
 
Join Date: Jun 2004
Location: Canada
Posts: 3,055
Default

Quote:
Originally Posted by PAUL K View Post
You can also modify an existing 4150 baseplate to work on a 4500 manifold.

Paul: Do you know if the flange area is large enough to fit the 4500 without an adapter? I realize the dominator is a larger 4 bolt hole pattern. Thanks

__________________
68 Firebird. IA2 block, 505 cu in, E-head, Solid roller 3650 weight. Reid TH400 4:11 gear. 29" slick.
Best so far 10.12@133 mph. 1.43 60 ft.
76 Trans am, TKX .81 o/d, 3.73 Moser rearend,
468 with KRE D-ports, Doug headers, 3" Exh.
  #17  
Old 11-11-2023, 02:47 PM
Tandyman Tandyman is offline
Member
 
Join Date: Jun 2006
Location: Northern GTA, Canada
Posts: 68
Default

I have a Holley 1000HP that I put a Quickfuel dual pattern baseplate on. It will not bolt on to any of the 4500 manifolds
that I have tried it on. It needed an adapter/spacer to get linkage/pump clearance on them all.
Kind of disappointing really .

Glenn

The Following User Says Thank You to Tandyman For This Useful Post:
  #18  
Old 11-11-2023, 06:42 PM
PAUL K's Avatar
PAUL K PAUL K is offline
Ultimate Warrior
 
Join Date: Feb 2004
Location: Sugar Grove IL USA
Posts: 6,255
Default

Quote:
Originally Posted by chuckies76ta View Post
Paul: Do you know if the flange area is large enough to fit the 4500 without an adapter? I realize the dominator is a larger 4 bolt hole pattern. Thanks
It's real close. We usually make a plate an adaptor out off a heat insulating plate.

__________________
Go fast, see Elvis!
www.facebook.com/PaulKnippensMuscleMotors
The Following User Says Thank You to PAUL K For This Useful Post:
  #19  
Old 11-18-2023, 10:11 PM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,627
Default

I run a 8896 1050 4500 on a victor and I foot brake. Engine is very responsive I bring it up to 1100 RPM and hammer it, no bog it just rips. I tried launching off a t-brake my 60' times were the same and I red light every time soi I don't use the brake. 473 cubes 330 cfm e-heads old style combustion chambers.

__________________
Tim Corcoran
The Following User Says Thank You to Tim Corcoran For This Useful Post:
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:10 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017