Hot Rods Holly carb question

How all u guy's and gals been. Been quite some time since I have been on here since my computer crashed a few years ago. Up and going again and looking forward touching base with many of you again. As it is I currently have a question on a Holley carb. Trying to identify it. Not a hole lot of experience working on cars quite yet but am mainly a Chevy - Gm fan. What I need to know is the CFM And anything else that would be handy to know about it. It has a double pump on it I believe and on the front side List # say's 6498 and under that has a I think either A letter D Or a O and 473 after it. I also see a 6R-4237 B on the side of it . also see a number on the base of it that reads 12R-5395 B. Any info on it as well as possibly a year as well as what it would fit which am fairly certain Gm would certainly be appreciated. Thanks

 

Have you checked the Holley website to see if there's info available there?

 

I didn't see anything on this carb

 

650 CFM

 

650 cfm Spread bore carb. I ran one for years on my 48 with a 350 in it, then on my son's 70 C10 with a 307 in it and later on my 71 GMC with the 350 in it. It's hanging on a nail in the shed now but is beyond worn out.

 

I am pretty sure that is a high performance carb Holley sold as a replacement for the Q-jet. They were never factory installed on anything. 650 CFM Double pumper with mechanical secondaries. They were good for performance,but not so fuel friendly.
"letter D Or a O and 473 after it" - This is a date code. I believe yours is 0473. 047 is the day of year and the 3 is for 1973.

 

get rid of it and replace it with the real thing a Q-jet

 

I have always heard that the Holley spreadbores combine all of the worst features of Quadrajets with the worst features of Holleys.

 

Its a 650 spread bore double pumper. just look up the list number

 

a q-jet has no bad features its simple ( to me ) ,to me the spread bore holley took a good design and did there typical thing and really made it confusing .

 

Wait a minute--- your computer crashed and you took a few years to fix it?
I get heart palpitations if my internet connection goes down for 15 minutes.

 

Thank you

 

Wasn't by choice. Divorce can slow things down a bit. Used buddies computer for a couple years till I got back on my feet again. Thanks for the info mike

 

thanks for the info

 

Thanks for the advice. Seems to be a love hatred on this carb.

 

Thank you so much for all the info. Certainly help me out a lot. Greatly appreciated!

 

thank you for the info. Some people seem to not like this carb but seems as if you have stuck with it and seems to have served you well. Not sure what I'm going to use it or not.

 

they are the black sheep of Holley , I have a box of them that people have pulled off and given too me , one was brand new ( 1 week old ) the guy couldn't get it to tune and was so pissed off that he bought a new manifold and put a square bore on it . IMo it was a big mistake on Holleys part .