Inliners International Forums General Discussion Engines The Right Carb

If I had a clifford water heated intake on a 250. What would be a good carb to match up. It's on a 66 chevy truck daily driver, I live in Canada so it will get very cold. I would like good power not a gas hog. 2 bbl or 4 bbl or 2x2 bbl singles what will work the best. Was thinking of a Holly 390 cfm 4 bbl.

I have an Edelbrock 500 on mine. I run it stock-tried rejetting but ended up going back.

390cfm 4bbl would be a good choice.

Have had a Holley before and was happy with it... Is the 390 4 bbl to big and should I be looking at a 2 bbl ??? What about mach or vacuum secondaries ?? Thanks for the help...

A two or foul barrel carb is up to you.
Of course when you floor a four barrel your milege will be worse than a two barrel,,,, but you will make typically make more power with a four barrel.

Vacuum secondaries will give you better milege.
Mechanical secondaries will use more fuel & typically give you better acceleration.

I believe you will probally get better milege w/a Edelbrock carb over a Holley.

As far as tunning A Holley would be easier to dial in.

Most people can't figure out how to property tune an Edelbrock carb.

Remember, in a six cylinder engine ,,your vacuum will drop down lower typically than a V-8 engine.
So, I would nornally run a lower vacuum rated power valve or on the Edelbrock carb(softer springs)

To really tune any carb in nicely, you should get a wide band O2 reader.I use the LM1 from Innovate
http://www.innovatemotorsports.com/
much better than seat of the pants feel,A.K.A.(butt dyno) or trying to read spark plugs.

MBHD

Yeah! The LM1 is the best "Speedeqipment" I got.

The guy that tune by ear are always way to rich, and there`s no better way to rejet than with that wideband sensor.

my ct2 Frank

390 4bbl isnt too much.

You should consider a two barrel Motorcraft/Autolite 2100 or 2150 series. Better than a Holley for many reasons.

MBHD hav you ever checked out the scientific carb tuning on the www.bob2000.com/carb.htm website. He uses an o2 with a volt meter for far less $. More like "our" style of getting thingsa done! On another note, has anyone turned their Holly carb sideways as someone mentioned the other day, I'm very curious. Herb 250 heated Clifford with headers 450 Holly with vacuum 2ndaries HEI. Anxious to hear comments.

Remember; it was a 1 bbl from the factory, so the 390 Holly would be the max for a (stock engine) truck.

With todays fuel prices, the 2 bbl "French" suggests might even be a better choice.

Good luck.

I had the Weber 32/36 on my truck and although I could get ok mileage, the power was never there.