I would like to know what Holley Carb. would bolt right on my all stock L48 auto with air. It has Vacumn secondary and electric choke. I assume its a spreadbore because of the stock looking manifold. It has a Holley( see pic) on it now but it's over 22 years old and probaby better to just replace it. Any ideas on a perfect replacement? 

I put a Holley Street Avenger 670 on my LT-1. 

Thanks for the info. I don't think thats a spreadbore carb. If I used that I would need a adapter plate?

I replaced my Q-jet with a Holly 4175 spreadbore

i can’t believe how the cost have gone up on these

bought mine at Summit 

https://www.summitracing.com/parts/hly-0-80555c

Brian - NCM Lifetime Member

73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
Leather seats, Seatbelt Plus 3point seatbelts, Pioneer CD player
Magnaflow Exhuast System

Yeah thats crazy..Thinking about changing manifold to Edelbrock and do away with the spreadbore.

A spread bore actually is a good carb.  With the primaries being smaller they sip a little less fuel when cruising.  And the larger secondaries add a punch when you mash the go pedal.

Jim Olson 

"The Toys"...!!!  Save the Wave!

Where I've been in a Corvette...!!!

Just can't believe the prices on them..I've seen anywhere from $657.00 to $900.00 for the exact same carb! 

Your cheapest option would be to rebuild your existing spreadbore. The next option that I would entertain would be to get a good Q-jet and put on it.

1973 L-82 4 spd

I was thinking about rebuilding it but it's aleast 20+ years old. 

Rather just get something newer. Open to the Q-Jet idea however they're just as old.

Mine's almost 50 years old and I'm getting ready to rebuild it again. Check out Cliff Ruggles book on Q-jets on how to rebuild and modify them. He also sells the rebuild kit for a reasonable amount of money.

The only thing I remember about a Holley Spreadbore is that I had a friend back in the seventies that put one on his '72 and not too long afterwards, put his Q-jet back on.

1973 L-82 4 spd

Like 73Shark said, there's nothing wrong with Q-Jets. 650 CFM IIRC? Relatively easy to rebuild, R&R, and tune. Not the best MPG, but come on: we didn't buy these cars for their fuel economy and save gas! 😄

Steve