Carb Recommendations for 5.7L Vortec?

[Lou C]

One thing you're going to have to work through is that the Vortecs do not have the heated exhaust cross over that the pre-Vortecs do in the intake manifold, so you will need to got to an electric choke conversion if you want to use a choke, or a manual choke conversion.
Remember that there have been no new Quadrajets since 1990 or so, all the ones you can buy now are "remanufactured" and some Qjet experts tell you to stay away from them, they are rarely set up right and can be combinations of different carbs. I have an original on my boat and it's an excellent carb when maintained in good condition. The other option to give you more choices is to use a square bore intake which allows you to use the Holley or Edelbrock.

 

[Scott Danforth]

holley side https://www.summitracing.com/parts/sce-355-1

manifold side https://www.summitracing.com/parts/sce-3584-1

modify as needed with gasket punch for the holes

 

[76SeaRay]

Both of my carbs Rochester and Holley have electric chokes. Even if I had a heated choke I would convert it. Anyway I look at it, I have to use a 4 hole spacer to seal the bottom of the Holley correctly with the gasket you show. The problem I have been having has been finding adapting it to the intake manifold. I think I found two spacers that should work. I will give this one last try.

So, the top down would be Holley Carb, Holley 4 hole gasket, 4 hole phenolic spacer, open square gasket, open adapter Holley square bore to spread bore, finally a modified spread bore gasket or self made gasket, and finally the intake manifold.

Gaskets as mentioned above, however, the adapter comes with gaskets including a slightly larger open gasket.

Phenolic 4 Hole Spacer -- ​

Canton Racing Products 85-154 Phenolic Carburetor Spacer (For 4150/4160 Holley 4 Hole 1/4")​

Open Center Adapter Spacer -- ​

Speedway Motors Universal Quadrajet Carb Adapter, 3/4 inch Open Center Part # 1351932​

 

[76SeaRay]

Little by little getting there with the Holley Carb. I figured out a stack up of gaskets and spacers so moved on to mounting the brackets for the throttle cable. As you can see in the pics below I went with the wrap around Holley bracket. I found the accelerator pump arm hits the bottom of the bracket in the front so the bracket has to be spaced above the carb bolt points. That is not a big issue, however, I also picked up the cable installation kit to go with the bracket and it doesn't fit correctly. The bushings for the swivel connection are too large in diameter and intended for a larger hole in the accelerator bracket on the carb. Even if the bushings were to fit in the hole, the swivel ends up being offset about 1 1/4 inches from center line of the cable retaining bracket. Anybody run into this problem and maybe know of a spacer that will work to move the swivel farther out?