Direct replacement for OMC 5.7 Rochester quadrajet

ss9940_2

Petty Officer 2nd Class
Joined
Apr 13, 2007
Messages
142
Hi there fellow iboaters!


Can any 1 suggest a direct replacement for a Rochester quadrajet? The engine is a 5.7 OMC, GM Engine. I would really need a "bolt in" carb, don't wanna modify anything.

Thanx in advance,

Alex
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: Direct replacement for OMC 5.7 Rochester quadrajet

I believe both Holley and Edelbrock offer marine versions of popular model carbs, but they will probably not bolt on directly. The quadra-jet has 7/8" primaries, 2-1/4" secondaries that make it somewhat unique. You might have to replace your intake manifold also.
I'm curious why you want to lose the quadra-jet? Mine has run flawlessly for many years.
 

ss9940_2

Petty Officer 2nd Class
Joined
Apr 13, 2007
Messages
142
Re: Direct replacement for OMC 5.7 Rochester quadrajet

Hey!

It's cause the old one is junk. Doesn't work right after 2 rebuilds. Plus, the fuel economy is supposed to be far better with an edelbrock or holley
 

KaGee

Admiral
Joined
Aug 14, 2004
Messages
7,069
Re: Direct replacement for OMC 5.7 Rochester quadrajet

Hey!

It's cause the old one is junk. Doesn't work right after 2 rebuilds.

Couldn't be the rebuilder, could it? :rolleyes:

Or another thought... maybe whatever problem you have is not the Carb? ;)
 

ron7000

Banned
Joined
Jul 10, 2004
Messages
498
Re: Direct replacement for OMC 5.7 Rochester quadrajet

Hi there fellow iboaters!


Can any 1 suggest a direct replacement for a Rochester quadrajet? The engine is a 5.7 OMC, GM Engine. I would really need a "bolt in" carb, don't wanna modify anything.

Thanx in advance,

Alex

direct replacement from holley is a model 4175. It is a spread bore carb, opposed to the traditional holley square bore and will drop directly onto whatever you had the QJ sitting on. So you wouldn't have to change your intake manifold or use a manifold adapter/spacer. But it probably won't be a complete drop in, things like the fuel line fitting and throttle cable bracket may need replacing and the holley has electric choke so you'd need to wire it to the ignition, all of which is simple and holley is pretty good with parts like that.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY-0-80552&N=700+115&autoview=sku
 

Coors

Captain
Joined
Dec 8, 2006
Messages
3,367
Re: Direct replacement for OMC 5.7 Rochester quadrajet

Couldn't be the rebuilder, could it? :rolleyes:

Or another thought... maybe whatever problem you have is not the Carb? ;)

What is the problem, exactly?
 
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