Carb heat soak? Or...?

[Kootenay64]

Hi all, hoping for some pro carb guidance here.
Have a 64 C10 w a 305 from a 86 camaro, had the truck for a year so far and among things to address has always been the carb. Came w a 4 bbl on an Edelbrock intake manifold. The truck has always run just OK but recently became very difficult to cold start, cranking for 1 - 2 minutes, once started ran ok. Figured since the carb was original to the engine went out and bought a new Edelbrock AVS2 500 cfm hoping to cure some of the issues. Although the new carb runs way crisper and running performance in general has greatly improved it is still very hard cold starting after running and being left for a few hrs or overnight.
I’ve read about fuel boiling off and emptying the bowl, how can this be fixed? Do the carb insulator gaskets work?
Thanks in advance for any help

[geezer#99]

An insulator will help.
A thick one like this.
https://www.summitracing.com/int/par...8711/overview/

How your choke is set up helps too.
As does your timing curve.
More initial needed likely.

[Dead Parrot]

Boil off is a known feature of that style carb. The spacers help. Make sure you get all the gaskets needed when you order one.

Is the manifold exhaust crossover blocked off or still open? Assuming your style manifold came with one.

If you have one, is the exhaust riser valve stuck shut? That can also cause poor performance and carb heat problems. Don't think 64's had them but possible one came over with the transplant.

[Kootenay64]

Thanks for the link geezer I’m ordering one today.
Not sure on the timing will check that as well.

[Tom]

Your in Canada? Heat soak is not your issue if so. I don't have issues with it in 118* AZ summer. Even if it did boil the gas out, the bowls would be refilled much quicker then a full 1-2min of cranking, thats a ton. Your carb needs tuning. Did you just install it out of the box or already do tuning to it?

[MySons68C20]

I agree with Tom....If your fuel pump is healthy you should see fuel at the bowls right away. I would look to see what your fuel delivery is on a COLD start.