6066 (1960-1966) GMC Truck Club - New carburator 350CFM vs 500CFM?

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- - New carburator 350CFM vs 500CFM? (https://6066gmcclub.com/showthread.php?t=48759)

Re: New carburator 350CFM vs 500CFM?

Quote:

Originally Posted by jagarra (Post 57665)

Thanks for all the information Big Block. Ordered one of them 4412 C as I don't like the looks of the shiny one as much.
Are there any issues hooking up the fuel lines and vacuum line for the distributor like thread pitch. Reason I asked, when I was looking at the Summit site, when you brought these Holleys up they listed some fittings like an AN6 with an inverted flare as something folks bought at the same time.

thanks again,

You're existing fuel line fitting going in the carb will fit the Holley, it's up to if you want to bend up a new line or just cut the old one and hook up rubber hose to it. For the vacuum line there is a port on the right side of the throttle body but I prefer just to use the vacuum straight out of the fitting in back of the intake manifold. I first did the Holley conversion back in 1975 at the age of 15. it was so simple all that was needed to adapt it was basic GM to Holley 2bbl adapter since the 305's intake base shared the same dimension as most other GM engines equipped with smaller 2bbl carbs

Re: New carburator 350CFM vs 500CFM?

Got my Holley today and installed it in my truck. I had to get a special fitting to adapt my fuel line to match the existing inverted flare fitting on the carb. (part # BQ248) from a local outfit that make hoses.
Tapped off the back of the manifold for the vacuum advance, throttle linkage worked OK using the small hole just below the large 1/2" one.
After I got it started it ran good considering I didn't touch any of the adjustments except the idle screw.

After the truck sat for a couple hours and I went to start it, it was pretty hard to start compared to the old carb. Not sure if it is not getting enough gas initially to start. Is a electric fuel pump recommended to address this issue?

MY choke cable is too short, so I have to deal with that tomorrow. I have a longer housing and inner cable, if I am lucky I may be able to change those items. I really want to keep the original knob for the choke since it matches all the rest.

Re: New carburator 350CFM vs 500CFM?

Normally its because your getting too much fuel on initial start up. Have had that happen on my 66's 292...converting to an hei helps the situation.

Re: New carburator 350CFM vs 500CFM?

TJ, you are right about too much fuel. This morning I went to start the truck, didn't touch the gas, no choke and it fired up right away. It even idled good. I'm gonna love this carburetor.

Still pondering what to do about the choke, was thinking of moving it to the hole just to the left of the ignition switch. Then using the old location for one of those wiper delay units. if I can get the guy to answer my e-mails. Then get a radio knob from Brothers for it so it matches the rest.

Re: New carburator 350CFM vs 500CFM?

Should be able to used the stock choke cable. Not long enough maybe?

Re: New carburator 350CFM vs 500CFM?

The stock choke cable was too short. I ended up moving it to the hole that was blocked off next to the ignition switch. Now the cable reaches OK , plenty of slack to route it in the engine compartment. I installed the windshield wiper delay in the old choke location. Found a bezel that matches perfectly and a repro radio knob matches really good, especially after you paint it flat black.