Quadrajet secondaries

[RoryH19]

Mind if I have that quad before you start kicking it?

Actually drove it today. Still not a fan of the quad. It maybe coming off soon.

 

[bedwards]

ok,, at a loss, no joy. Exactly the same behavior.....

 

[Rusty Nail]

Should you decide to go with the Holley, get a 9895. Very tune-able spread bore, with vacuum secondaries that will hook up easily to the stock manifold. It has an electric choke and the fuel line should line up also. Buy the Secondary vacuum spring kit too. Remove the heaver black spring and install the purple spring, if I remember the spring colors.

Great post! Too bad no pix tho.
We're enjoying this terrific thread! -us readers

 

[82sbshortbed]

Im surprised that youre having problrms with the quad. Ive found them to be a vrey reliable carb and holley to be a finicky bitch to tune right. Plus they have a ton of info out there for rebuilding them. But, maybe that's just my experiences with Holley. I have a new Quadrajet on the 305 and an Edelbrock on the BBC. Edelbrock was on the BBC already.

Just my .02

 

[bedwards]

Its surging which it was doing before the rebuild, has a massive flat spot when the secondaries should be kicking in, missing under hard acceleration and popping in the exhaust occasionally like its too lean.
At the risk of sounding like I was throwing parts at it, I changed the plugs and the ignition module. Still no joy. Its got to be carbuerition.

 

[Rusty Nail]

I remembered that dumb.ass. little tint maybe 3/32 ALLEN HEAD screw that you gotta sacrifice a wrench and bend up to get to...know what i'm talkin about?

 

[Turbo4whl]

Great post! Too bad no pix tho.
We're enjoying this terrific thread! -us readers

I can add some more info for you Rusty, et al. When I started in the trade and the company trucks has gasoline engines they all had Holley carbs. Medium duty Fords with 330/360 engines, Internationals with 345,392 and 501?BB, Rio big 6 inline, and oh yes MD GM's with 366, 427 all built with Holley carbs. So I learned and knew Holleys.

So in 1974 when I bought my K5 with the 350 I asked the older drag race motor heads, What do I need to do to wake this engine up? You need to re curve the distributor, add some headers with a better flowing exhaust. Yeah get rid of the air pump and EGR valve too. What happens when you make the exhaust flow better? More air flows through the engine and carb. The carb is now too lean. What happens when you remove the EGR? The EGR was dumping un-burnt hydrocarbons into the intake (fuel). The carb, too lean again.

Now you want to make the quadrajet run richer. Back in the day you could go to the dealer and order different metering rods and jets, wait a day or two until the arrived and try them out only to find you need a different set. Back to the dealer and order again. Or maybe just buy a Holley from the speed shop. Need some jets or metering plates, the shop has a whole case of different jets. You could even try a set and if you wanted a different set they, (my local shop) would swap them for free.

Like I said I was very familiar with Holleys, so around 1975 or 76 I woke up my K5 with a set of Hooker long tube equal length headers, re-curved dizzy (as you all call them) and a Holley 6210 650 CFM spread bore carb. That Holley mounted on the stock intake with a plate bolted over the EGR ports. Yes there is more you can do, different intake, different cam, porting etc. But the most bang for your buck is to open up the exhaust, and when you do this, you need more fuel than the stock carb will provide.

Rusty a picture for you, 6210. More about the 9895 later.

6210

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9895

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[Rusty Nail]

Oh for some strange reason I had a fleeting fancy with the idea of spreadbore Holley carbs while back.
No clue what i'll do with an old 450 Holley from the Z system I managed to rustle up.

https://books.google.com/books?id=LdkDAAAAMBAJ&pg=PA69&lpg=PA69&dq=Holley+300-28Z&source=bl&ots=BvLf4jGF8X&sig=WA0KaXM2rUQBo1EDm4TD5Pxv5bE&hl=en&sa=X&ved=0ahUKEwi7063oiYDUAhUp3IMKHVXcAi0Q6AEITjAG#v=onepage&q=Holley 300-28Z&f=false

i'll try to remember some carb number I was really keen on.
Thanks for the reply.

I own a 300-28Z intake manifold that has never been installed. -my 2nd!

 

[Turbo4whl]

I remember that intake. I was drooling over it for my K5. I think they must have cast it out of gold or something. Never pulled the trigger.

 

[bedwards]

Ok, I guess I am officially one of those people (Parts re-placer)
It was the fuel pump all along. It runs really well now. It should, its got a bunch of new parts. It faked me off when it pumped a quart of fuel 30 seconds and I didn't have the gauges to check pressures then.
It wants to tink just at tip in if I go to 12 btdc so it is set at 8 right now.
Should I back off the secondary spring or leave it? It is at roughly 1 turn from just touching right now. Factory was 3/4 turn.


Many Many thanks for all your suggestions.

 

[82sbshortbed]

Glad you found the problem. I was going to be surprised if it was your Quadrajet because they are a very reliable carb.

Good thing you didn't swap carbs that'd be much more expensive and not fixed the problem.

 

[bedwards]

I've had a crash course in how to tune one. It would have cost a fortune to get all the adapters to make a Holley or a Edelbrock work on my stock truck. I really think if I were to change I'd go to TBI.