CARB HELP - what kind

HI Guys.. needing an answer ASAP
I have a holly carb,.. can't find any info on it on any web sites.
If I give you some info off the carb, maybe someone can help me determine what it came off of and if I can use it.
It is a 4 barrel carb.
Has the numbers list-1850-3 on the 'top' (back side of part that sticks up) and under those numbers are 2087
on the bottom (where floats are) are the numbers 34r-2178B
under that is a 2.
can anyone help me with the year, etc
I should also mention this one has all four holes the same size (not two small ones and two huge ones)
THANKS
Chris

PS this is the carb I was hoping to use on my street rod for the good gas mileage

 

1850 is a standard model 4160 vacuum secondary, single inlet, 600 cfm carb. This is a universal replacement carb not a factory piece. rebuild kits are like $20 bucks from summit, jegs, etc. You can use it on any square bore 4 barrel manifold. Mileage comes from tuning it right / drivetrain combo. I've run on moderate 302's and got 14 and factory 400's and got 16.

JB

 

hhuumm
I was talking to a 'carb guy" and he said this shouldn't be run on a 'Chevy' application. It's better for a small ford. He said a chevy it will run lean and be bad for the motor.
He suggested a 650 cfm carb and said that it would get better gas mileage for me than the 600cfm I had

 

I'm running one on a 400 chevy now. It will flow enough air for factory heads. If it's lean change the jets.

The next step is a 3310, also a model 4160 , but its 750 cfm, has center hung floats, and dual inlets.

 

since I last posted... I called "tech support" at Holly Manufacturing.
Guy there said with a 305 I needed nothing bigger than a 570 cfm.
I cold him it would go into a pickup probably a little more than 2 ton in weight... and he said if I was striving for better gas mileage a 600 might be a suggestion and work with the jets.
But nothing NEAR a 650cfm.

everyone it seems wants 250 bucks to rebuild this old carb I had....
Turns out I bought a brand new chrome one from the store for $260 bucks
I guess it pays to do your homework.
Thanks for the help guys