Carburettor advice

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Chargingatchya
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Carburettor advice

Post by Chargingatchya »

Hey guys…

I hope I’m not being a pest, or cluttering these forums with my issues but I thought I’d start a whole new thread for this as it’s a little more specific in my build, and something I’m
Struggling with a little..

I’m looking at carbs, and being completely new to them am a bit overwhelmed with the amount of info and various options.

Thanks to the great advice, blue, Pete, MattH, Dave and god knows who else I forgot to mention. Your advice has give me a platform to start my research with!

So I currently have a Carter AFB that came on the charger. The charger is a 383, auto column shift originally a 2 bb car. I don’t know if the cam has been upgraded at this point. The trans, engine and rear is original to the car as numbers match (rear obviously isn’t numbered but looks to be original and not tampered with and fits what came with a 69 383) The 4bb Carter carb has been added later. It comes from a 64 Pontiac bonneville or Catalina I believe (this took a little research)

Blue recommend a double pump carb, has anyone had experience with this on an auto car? as reading up it seems this is a bit of hit and miss…

I won’t be racing or upgrading much at all. I just want a responsive and reliable street car for Sunday cruising. I don’t even mind an manual choke as I’m of the believe the less automated the less there is to go wrong.

I was planning to purchase a 650cfm Holley, Vacuum secondary carb with a manual choke. Does this sound like it will fit the bill? Is it a straight forward one off one on then off for tuning or should I be factoring in tuning kits and other issues that I have not realised?
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Pete
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Re: Carburettor advice

Post by Pete »

For your intended purpose, I think you have it right if you can be bothered to rig up a manual chock.

I don't tens to use any Chokes on American Cars.
A few pumps of the accelerator and a fast idle for 30 seconds and you are good to go!

If you are a bit "Racey!" or have a 4 speed, I agree with Blue on the "Double Pumper" solution - again without a choke!!
Pete Wiseman; Cambridge.

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mygasser
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Re: Carburettor advice

Post by mygasser »

another thing to check, is your inlet manifold a square bore or spread bore type? holley from memory do both types in a 650 vacuum secondary. getting the right one for the inlet will mean no need for an adapter plate which is better.
neil.
Chargingatchya
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Re: Carburettor advice

Post by Chargingatchya »

mygasser wrote: Mon Nov 22, 21 10:51 am another thing to check, is your inlet manifold a square bore or spread bore type? holley from memory do both types in a 650 vacuum secondary. getting the right one for the inlet will mean no need for an adapter plate which is better.
neil.
Thanks for the top tip mate, again saving me future aggro and cost 👍
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Pete
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Re: Carburettor advice

Post by Pete »

Neil makes a very good point, it would be wise to check this out first.

If possible, try to avoid using a Spacer / Adapter plate as under-hood clearance can quickly disappear.
Pete Wiseman; Cambridge.

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Chargingatchya
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Re: Carburettor advice

Post by Chargingatchya »

So I’m looking at these, I’m not budget conscious on this, but it does seem to fit the bill almost perfectly for what I want.

Il also be buying an electric to Manual choke conversion kit, as I don’t want an electric choke. Single fuel feed, vacuum secondary and I will double check if fits my intake type, but I believe it’s right. Easy to tune so should be manageable by a novice like me.

I’d like it to have been 650 cfm but to be honest, I can’t see it making too much difference and soon as you select 650 it seems most need dual fuel lines. Having just finished installing the fuel system I really don’t fancy having to swap parts out again…

Anyway here’s the carbs I’m looking at…

https://www.holley.com/products/fuel_sy ... s/BR-67270

https://www.holley.com/products/fuel_sy ... s/0-80457S

Happy to hear your thoughts!
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Pete
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Re: Carburettor advice

Post by Pete »

Personal taste but I would go dual line every time - I know it is more work and hassle. I don't like the Transfer pipes between bowls.

I would always go for a carb with dual metering blocks as well, I don't care for the metering plates. I like 4 corner idle as well but not essential.

Have you checked out the 670's - they are often quite a nice compromise....
Pete Wiseman; Cambridge.

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MilesnMiles
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Re: Carburettor advice

Post by MilesnMiles »

Just an alternative view. I usually run Holleys and don’t mind doing basic tuning. Don’t forget that both Pete and Blue are very experienced with tuning carburettors.
On my recent Barracuda I wanted a simple bolt on and go solution. I chose an Edelbrocks 500 AVs for the 273 motor, a 650 is also available.It ran perfectly straight out of the box, it has tunable secondaries and is a much better carb than their basic version. Inexpensive, simple, single fuel line.
Real Steel stock them
Looks like this https://frsport.com/products/edelbrock- ... ToQAvD_BwE
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Blue
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Re: Carburettor advice

Post by Blue »

Have a look at Quick fuel's version of the Holley carb. I bought one of their 650 double pumpers for my 360 and it ran perfectly out of the box with just the usual setting up. It's a lot of carb for the money.
https://www.holley.com/products/fuel_sy ... arts/Q-650
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Chargingatchya
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Re: Carburettor advice

Post by Chargingatchya »

Blue wrote: Tue Nov 23, 21 9:05 am Have a look at Quick fuel's version of the Holley carb. I bought one of their 650 double pumpers for my 360 and it ran perfectly out of the box with just the usual setting up. It's a lot of carb for the money.
https://www.holley.com/products/fuel_sy ... arts/Q-650
Thanks for that mate. Will this be okay with an auto?
Chargingatchya
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Re: Carburettor advice

Post by Chargingatchya »

Pete wrote: Tue Nov 23, 21 8:05 am Personal taste but I would go dual line every time - I know it is more work and hassle. I don't like the Transfer pipes between bowls.

I would always go for a carb with dual metering blocks as well, I don't care for the metering plates. I like 4 corner idle as well but not essential.

Have you checked out the 670's - they are often quite a nice compromise....
I will check them out! Is a dual feed just a matter of T’ing of the supply after the pump? Should I be upgrading the pump also in this case?

What are the benefits of a dual fuel line? Just a smoother transition of fuel to the Venturi which will translate to over all more reliable and smoother operating of the carb I’m guessing?! Or is it more an aesthetically influenced reason you prefer?
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Pete
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Re: Carburettor advice

Post by Pete »

Yes, the Float bowls are Tee'd together.
Usually people run twin output Holley Style fuel regulators and feed each output side of the regulator to each Float bowl, give more consistent supply.
Easier to tune without having to dislodge the transfer tube and "O" rings which to my mind are a restriction and potential fault liability.

As with most things, personal taste....
Pete Wiseman; Cambridge.

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mygasser
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Re: Carburettor advice

Post by mygasser »

if it's just going to be a road car something simple for a dual feed holley like this will be fine https://www.jegs.com/p/Holley/Holley-Du ... 0+TO+50%5D
neil.
Chargingatchya
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Re: Carburettor advice

Post by Chargingatchya »

mygasser wrote: Tue Nov 23, 21 5:08 pm if it's just going to be a road car something simple for a dual feed holley like this will be fine https://www.jegs.com/p/Holley/Holley-Du ... 0+TO+50%5D
neil.
Thanks Neil. That’s excellent saves me mocking something up and it looking crap.

I think il be going with this, plus Petes recommendation of a dual fuel line and a regulator plus blues recommended carb! It’s was definitely worth asking 😉
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Pete
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Re: Carburettor advice

Post by Pete »

CAUTION REQUIRED.

You need to make sure the Fuel rail matches the actual carb.

IF it has a secondary metering block, the Fuel Rail needs to be LONGER as the spacing between Float Bowls is different.

Select the Carb first and then the Fuel Rail if you go that way.

Again - personally, I use AN Braided Hoses and proper fittings into the Float Bowls from the Regulator..... slippery slope.... makes jet changes and servicing easier..... I'll get me coat.....
Pete Wiseman; Cambridge.

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