Engine Tech
> Carburetion & Fuel sytems
User Name

sponser links

Thread Tools
Old 05-15-18, 11:22PM   #1
Stubborn old goat
keith's Avatar
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 650
Default Square-bore carbs 3.75x3.875

Looking to rebuild 2 same model # cores that will bolt directly to my Offy 5499 DQ manifold without an adaptor, must have above bolt pattern dimension. I read this is the original 4 barrel pattern from the 50's. Source lists these as indicated below, there may be others with this pattern, am interested in them as well .. especially if 2 are available with same model #s.

Carter WFCB early
Holley 2140
Rochester 4G series
Stromberg 4A

I have 2 4360's which take an adaptor to mount to intake, may interfere with hood clearance and not have performance potential I desire. Would like to try both setups for hood clearance and performance and choose what works for me best.

I like Quadrajets alot and would enjoy expanding my Rochester skills rebuilding 2 4Gs. If they fit properly they might be my best no adaptor setup. Did just get a Carter book, like my Roe/Fisher Rochester book better tho.
keith is offline   Reply With Quote
Old 05-16-18, 12:50AM   #2
Gach's Avatar
Join Date: May 2003
Location: ....
Posts: 19,463

Sorry canít help you
The things they hide, the way they spin things, the excuses that they make and the things they omit.
Gach is offline   Reply With Quote
Old 05-16-18, 01:26AM   #3
Stubborn old goat
keith's Avatar
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 650

Did you ever work 4bbl carbs with that flange size and note results? I have not, only q-jets and Holley's 4150/60's with larger bolt pattern. Not sure there was an AFB that size ... Carter started with WCFB went to AFB then to AVS then Edelbrock(AVS) ... not sure Ive ever seen a Rochester 4G it was before Q-jet, am not sure that equals a Rochester 4-Jet which I just found several of on E-bay in my price range. I will most likely start with 4360's. Never seen a Holley 2140 or Stromberg 4A although I have no aversion to trying them if I can get a pair that will fit with no adaptor.
keith is offline   Reply With Quote
Old 05-18-18, 11:13AM   #4
Ram Air V Guru
Join Date: Jul 2002
Location: long beach,california
Posts: 1,927

Keith,ALL pre 67 pontiac 4 bbl carbs used the Carter AFB 4bbl carbs.I believe pre 1958 used the Rochester 4 bbls.The 60s AFBs are considered a square bore carb as compared to the Holleys which are a wide bolt spacing square bore.Offy makes the correct adapter that bolts to the Offy intake.I believe they actually made a adapter that had both the AFB and Holley bolt patter just like MANY square bore carb gaskets have.Tom
tjs44 is online now   Reply With Quote
Old 05-19-18, 06:55PM   #5
Stubborn old goat
keith's Avatar
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 650

Thanks Tom, spoke with a fellow close to you in Monrovia, Paul at Paul's Carb shop. He was referred to me by the Offenhauser tech rep. A Pontiac guy too as he has a 66 GTO fully restored in his shop now. He said he had a 5499 Offenhauser dq manifold like mine in front of him and 2 small bolt pattern Stromberg 4A's that would bolt to it without an adaptor bolt-hole wise BUT ... the throttle shaft actuating arms hit top of manifold runners on the lower front carb. I had seen this, even with the adaptors I have for my 4360's that raise carb about .750" the front throttle arm hits .. was just figuring I needed thick gaskets. Just discovered the gaskets in my Offy kits don't appear to be right ... they look relatively simple to make, will just cut my own, was going to trim adaptors as well as they have excess material overhanging carb flange. Trials and tribulations Guess this manifold never worked without an adaptor with any carb, front carb anyways ??
keith is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
what's the difference between 780 and 850 Holley ? Zedo Carburetion & Fuel sytems 7 10-25-15 03:29PM
Seal Power Gapless rings Gach Engine Tech Discussion - Street or Strip 25 05-31-09 09:52PM
flow bench comparison- Superflow vs. custom entire flow path- CV1 heads get thumbs up Zedo Grape Vine - General Discussion 11 02-26-08 09:48PM
IA2 Block bore problems? Check pics 2fast4u Engine Tech Discussion - Street or Strip 35 11-01-07 05:08PM

All times are GMT -3. The time now is 04:09PM.

Featured Ads
Ken's Speed & Machine
Mayhem Turbocharging

Carter Cryogenics.  What can we freeze for you?

Pacific Performance Racing

Central Virginia Machine Service.  Home of the Injun Engine!

All Pontiac Engine Kits

Larry's Auto Machine.  Full serivce auto, marine machine shop, domestic and foreign.

Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
2001 - 2007 PontiacZone.com
Page generated in 0.07216 seconds with 25 queries