Just saying hello and needin a bit of help with truck

[Oldfart]

Hi Folks, for many years i have been a diehard chevy fan, but after many years of riding and driving my cousins 79 Dentside I am a convert and now own a 78 SWB 4x4 dentside.
And there inlies my issue, it had a broke down 400m in it, it now has a 1990 460ci with less then 80,000 miles on it, converted from EFI to a holley 4160 750, the motor ran like a top before i installed into my truck and now after converting it to carb it blubbers like it's gettin too much fuel even after warmed up. I'd appreciate any ideas / help. Thanks!

 

[Beach66Bum]

Welcome to FTF!
Is the Holley a new carb? Have you checked the float level? Jet size?

 

[Oldfart]

Welcome to FTF!
Is the Holley a new carb? Have you checked the float level? Jet size?

Yep, brand new from holley. primary jet size is 72, 6.5 power valve.

 

[Jasperrc]

Have you done any tuning of the idle mixture? Might be worth putting a vacuum gauge on it to make sure it's not running too rich.

 

[Oldfart]

I did. I started with the factory settings on a warmed up engine, timing is at an intial 12degrees, vacuum guage hooked up and slowly turned mixture screws inwards to get the highest reading on vac guage which right now is a steady 29.5 inches of vacuum.

 

[Jasperrc]

Does it still have the EGR valve? Recently had some issues with mine and similar symptoms.

 

[Oldfart]

Jasperrc, there isn't any smog, egr, or emissions devices of any kind, the motor is as basic as you can get. Going to do a little timing advancing on it and lower the floats on the carb with a good dose of cross the fingers lol.

 

[94LCALDERA]

hello

 

[twday]

Have you checked your fuel pressure? Too much fuel pressure and the fuel will fill the bowl and come out the vents. Not enough and you will starve the carb. Install a Mr. Gasket dialable fuel pressure regulator and set it at 4 lbs for the 460 with a 600 carb. It may take 5 lbs for the 750, but start at 4 lbs. Also you need to be running 93 octane on the 460. 87 won't do it.

 

[Oldfart]

Hi twday, i actually have the regulator you mentioned and i had it set originally to 4lbs and it's now at 5lbs with the holley 750cfm double pump. using holley's sight plugs you can see the fuel is roughly almost a quarter of the way up the plug. still got a few things to do like change plugs, and get rid of the Accel wires, adjust the float level down a bit and add a bit more timing, and then i'll update on where i'm at. the ol bones don't move so quick anymore in a cold shop lol.

 

[twday]

Sounds like you are well on the way to bringing it into being well tuned. I have the same set up on mine and had to experiment to get it just right. And the cold shop? Wow, do I know how that feels on the old bones. LOL