New Holley Choke Plate Shaft is too Fat

[unclebrad]

I recently bought a rebuilt Holley 800cfm carburetor (list 4780) to replace the dual quad setup on the 409 that I have in my truck. I like the idea of more simplicity.
But, being pretty much clueless about carbs, I didn't notice that there was no choke plate or linkage for a choke on it.
I was pretty sure that the parts must be available, and I am willing to learn new stuff. The guy at Holley assured me that they were available, and was very helpful by giving me a list of parts to buy. (I'm including a picture of the parts that I bought, just in case someone else decides to take on this kind of thing. My order total was about $130)
Once all the parts arrived, I took them out to the garage to try to get familiar with everything.
The Choke plate shaft is too fat. The guy at Holley said that they don't have another size.
I measured the shaft at 5/16" diameter, and the hole is about 1/4" (a 1/4" drill bit fits in the hole - not tightly, but a 9/32" bit doesn't go in.)
So, finally, my question is - where am I going to find the right size choke plate shaft?
Or, do I try to drill out the existing holes?
Or should I just cut my losses and buy a new Edelbrock carb? ;-)
Not a good start that the first thing I checked is wrong. (And it looks like there are a lot of steps to go.) But I am hoping I can get through this with a little help.
Thanks.

[crazy longhorn]

If you like tuning Holley carbs(I do)....you will not like that Edelbrock carb. My thoughts go like this....3.to/4 flaps on the peddle, & lite that booger off. You may need to keep your foot on the peddle, to keep her running......if she runs good after warm up, you are good to go I would not drill the top of that carb. You can probably source a 750 or 800 DP for parts, & have all the pcs that you need. Dont be afraid of that mechnical choke, I have ran plenty of them....no issues. Best of fun,Longhorn

[RustyPile]

First off, that 409 must be one hellova engine to need a 800 CFM, double pumper, mechanical secondary carburetor built for all out big displacement high reving engines. If your engine is street driven, you need much less carburetor.. Something like a 650 CFM, vacuum secondary carburetor.. BTW, if you don't know much about carburetors, an Edelbrock is the last thing you need...

We need to know more so we can better advise you. Tell us more about your truck/409. How and where you drive it. Engine specs (internals), transmission, torque converter, etc.....

[unclebrad]

Originally Posted by RustyPile

First off, that 409 must be one hellova engine to need a 800 CFM, double pumper, mechanical secondary carburetor built for all out big displacement high reving engines. If your engine is street driven, you need much less carburetor.. Something like a 650 CFM, vacuum secondary carburetor.. BTW, if you don't know much about carburetors, an Edelbrock is the last thing you need...

We need to know more so we can better advise you. Tell us more about your truck/409. How and where you drive it. Engine specs (internals), transmission, torque converter, etc.....

Thanks for the heads up. I figured that, since I was removing two 650 cfm carbs, 800 would be ok. I am not looking for something to race with, but will mostly use it as a cruiser with some occasional foot-to-the floor moments when I think I can get away with it, and am interested in hearing your advice. I can always sell off the parts I have here if another route is better.

The truck is a 55 Chevy Cameo. the Engine was 400hp from the factory in 1963. The dual carb setup added 25hp to that. I would have been happy with totally stock but the guy that I bought the engine from rebuilt it with a mild cam.

The transmission is a 700r4 automatic.

Unsure about the rear end but it is stock. I think a lot of them were 3.9 to 1.

If I live long enough, I will probably make several changes to the truck, like brakes, suspension, steering, wheels, a/c. But getting it back on the road would be a good start.

[RustyPile]

I'm curious.. Why did you remove the 2 X 4s and go with a single carburetor.. Were they problematic? Multiple carburetors on the street usually are.

[RustyPile]

Nice looking old truck.. Just the body style for a "W" engine.. I'm not partial to single inlet Holleys, but I wouldn't kick one out of bed.. Here's a link to Holley 600 CFM.. Although it's a single inlet, it would be an excellent choice to go with your 700R4 transmission.

https://www.holley.com/products/fuel...parts/0-80457S

You can probably get it cheaper from Summit, plus they won't charge shipping.

[geezer#99]

Why buy the Holley?
One of the two carbs you already had would work fine.

You got pics of the original 2 carbs on the intake?

Curious to see the set up for the 700R4 tv cable.

[unclebrad]

Sorry, but I can’t show you a picture of the tv cable on the dual carb setup because I decided to go single carb before working that problem out.
I took out the dual carb setup precisely to help simplify things like fussy carb syncing and configuring the tv cable.
As far as using one of the 2 carbs, I just can’t break them up. They are part of an original 425hp 409 dual quad setup and selling them together will be easier if everything is there.

[geezer#99]

Original 409 dual quad set up, eh!
I’d still like to see pics of it.

[unclebrad]

Originally Posted by geezer#99

Original 409 dual quad set up, eh!
I’d still like to see pics of it.

I only have a few pics of them on the engine. Added a couple with the Holley and original valve covers, which I added to get away from the hot rod vibe...

[geezer#99]

Thanks for the pics!
I was just curious about the fuel line set up. When I put togethor a dual quad for my 350 many years ago there was a top plate in the big box of carbs I had that had the fuel inlet on the front passenger side. Your pic shows it must have been from a 409.
Buddy of mine gave me a chromed offy intake and a big box of various afb carbs and I put togethor a like pair and ran them for awhile.
What is the list number for your Holley. That number might give a clue as to it’s origin. Older ones might have a different size cross shaft for the choke plate.
‘Twas mine I’d opt for a new Holley 3310 750 vs carb that’s compatible with a tv cable for your trans.

[crazy longhorn]

Originally Posted by geezer#99

Thanks for the pics!
I was just curious about the fuel line set up. When I put togethor a dual quad for my 350 many years ago there was a top plate in the big box of carbs I had that had the fuel inlet on the front passenger side. Your pic shows it must have been from a 409.
Buddy of mine gave me a chromed offy intake and a big box of various afb carbs and I put togethor a like pair and ran them for awhile.
What is the list number for your Holley. That number might give a clue as to it’s origin. Older ones might have a different size cross shaft for the choke plate.
‘Twas mine I’d opt for a new Holley 3310 750 vs carb that’s compatible with a tv cable for your trans.

Good call on the 3310 Holley.....I have run them on the street, from 355 to 461 inch engines On the 350, I leaned the primary jet a couple numbers... no problem with the big Olds. I did run a purple spring in the secondary on all apps, but was playing low gears(4.10s), & a stick shift trans. Longhorn

[unclebrad]

I found the proper shaft (with plate) on ebay. It should be here within a week or so.
But I'm liking the idea of starting fresh with a new carb. I'm not feeling very confident about the current one. I'm kinda feeling like it has some bad juju...
As far as the tv cable goes, I made up a plate for the current carb, that gives the right geometry. You can see it in the photo if you can blow it up.
Really appreciating all the input.

[geezer#99]

You’ve got enough invested in parts so mights well put it togethor.

[unclebrad]

You are right about that. But I'll still consider getting a new one. I can probably sell this one for what i have into it.

[crazy longhorn]

I still agree with geezer.....run that 800 DP ,& give it a try! I will say that I had an 800 DP on my OLDS 455+.030......swapped to the 3310 750. I thought that it would show me more mileage....it did not show me much, & the 800 DP had more kickBeing that you have the parts, I would try it! Just my thoughts....Longhorn

[unclebrad]

Yeah, nothing to lose I guess. And easier to sell all put together if I decide to take it off...