Holley carb

[Gmc1985classic]

Hey just wondering if anyone knows a lot about carburetors. I got an 85 seirra with a 327 bought a holley last year had no luck with tuning it just right, went on holley website found the four idle screw video tried it out with no luck. My vacuum only seems to get better when the idle mixture screw is all the way seated and the truck runs much too rich at 1 quarter turns out, this is the factory setting they tell you. Any thoughts would be nice

[KARNUT]

It's been a long time, most of the time people get in trouble buying too big of a carb. Usually a 600 vacuum secondary holly would serve most people. Could be your problem.

[diyer2]

What size carb? Agree with Karnut.

Pull the/some plugs to see the color.

[Heavy 5.7]

Throw it in the trash and run a Quadrajet.

[barry G]

holley is good.

just know cfm of your engine. compression, cam values.

lots of instruction, very common.

 

even a wimpy 327 can go fairly big. Some had 2 barrels, grandma cars.

Over doing cfm can take a map sensored msd digital...instead of the infamous cough.

 

I made my own rochestor for a 1.8L boxer..

280 cfm, one 43mm throttle valve. I catch a retard blip with map sensor on the msd box. Usually reserved for turbo engine retard.. I found other uses.

I do limit to 6500.. it can blow itself up trying into the 9k.

 

have fun. Once you get the carb right for you.. it works all year.

a wideband sensor for cutsom setups, or flying blind, it is a good gadget to have.

[Gmc1985classic]

Diyer 2 its a 650 cfm plugs are black but knew that already clean them up and try a much leaner tune. Its no stock 327 have the edelbrock intake msd ignition system hooker headers dual flowmasters i believe the engine came out of corvette