Edelbrock Adapter questions

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Thesiger

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I have a 1986 K10 with a .305 and a VERY trash quadrajet that had an attempted rebuild.

Just bought a used Edelbrock 1406 600 cfm to start over. I know I need an adapter, what what one? I've heard #5765 or #2696 as useable adapters, but can anyone confirm? And is there anything else that needs modification when changing to this carb on a chevy small block? Thank you.
 

bucket

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There's a lot of opinions on this subject. A "four hole" adapter would be ideal to retain stock type drive ability, BUT a four hole adapter also highly restricts airflow past the primary butterflies as the throttle is opened, which would make the "open" type adapter a better option.

Really though, the best option is to keep with a Quadrajet or get a manifold to match the square bore style carburetor.
 

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Not sure about the adapter but get a bypass fuel regulator to keep from flooding the engine and a phenolic gasket to keep the carb cooler and eliminating vapor lock. Worked wonders for me.
Bypass regulator not needed on 86 k10 factor pump is a bypass pump
 

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There's an older Holly manifold around, could it work to just pair this Edel and set it on top of my .305?
 

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If it's a squarebore manifold,than yes. I'm assuming you got a used edelbrock. How do you know it's good? Another thing that comes to mind,verify you have good compression all the way around,good plugs,good wires,cap and rotor,no vacuum leaks,working vacuum advance and centrifugal advance. I say this because lots of people throw a carbureator at something,next thing is " I changed the carbureator but it still doesn't run right"" I put on a fuel pressure regulator but it still doesn't run right" I jetted up,I jetted down. Oh ran compression I've 2 holes down. Oh just found out my vacuum advance doesn't work. Etc. Etc. Etc. Carbureators and oxygen sensors the most commonly over replaced items IMHO.
 
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bucket

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If it's a quarebore manifold,than yes. I'm assuming you got a used edelbrock. How do you know it's good? Another thing that comes to mind,verify you have good compression all the way around,good plugs,good wires,cap and rotor,no vacuum leaks,working vacuum advance and centrifugal advance. I say this because lots of people throw a carbureator at something,next thing is " I changed the carbureator but it still doesn't run right"" I put on a fuel pressure regulator but it still doesn't run right" I jetted up,I jetted down. Oh ran compression I've 2 holes down. Oh just found out my vacuum advance doesn't work. Etc. Etc. Etc. Carbureators and oxygen sensors the most commonly over replaced items IMHO.

And ECM's.
 

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Most everything else common has been gone through, though it is a fairly tired little engine. make's around 35 p oil pressure. plugs, wires, cap, rotor, haven't vacc tested, bought the tool though. the used Edelbrock I got came off a running dodge magnum so not too worried about that. All good stuff guys
 

Ricko1966

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Something else just came to mind. You are going to have verify,TV geometry,if you have a 700r4 or just budget for some replacement 700r4s
 

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A 700r 4 uses a cable that resembles a th350 kick down cable. The difference is the 700r4 uses that cable to regulate transmission line pressure. If the geometry on your throttle linkage is not correct,the cable does not pull the correct amount to keep line pressure where it needs to be. It is the biggest killer of 700r4s IMHO. In #8 post you say you've covered everything common,I would consider a compression test and a vacuum reading common,and way more important on a drivabilty issue than oil pressure. You can have great oil pressure, but a flat cam,broken rings,worn rings,vacuum leaks and burnt valves have no affect on oil pressure.
 

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Look at the transmission pan. If it's basically a rectangle, it's a 700r4. If it looks like a square with a corner cut off, it's a th350.

A search of chev automatic transmission id will give you pics.
 

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Bypass regulator not needed on 86 k10 factor pump is a bypass pump
I don’t want to talk out of turn, but my guess is that he’s speaking of limiting the psi for the Edelbrock since they don’t like much more than 5.5-6 psi.
 

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I don’t want to talk out of turn, but my guess is that he’s speaking of limiting the psi for the Edelbrock since they don’t like much more than 5.5-6 psi.
Quadrajet uses same fuel pressure,and what his 86 should have, if he is running the factory pump, it is a mechanical pump,and built in bypass. It should be non issue. I definatly wouldn't plan on a bypass regulator before I had a checked fuel pressure.Me? I'M running an electric pump pushing through a factory three port pump,so I bypass excess fuel back to the tank,the pump never dead heads,and I don't blow my needle and seat open. I am running q jet on that truck.I have 2 others with edelbrocks ( on there when I got them) no pressure regulators. Maybe 98% need it and I just got lucky with the 2% that don't. I think more realistically it should be a case by case situation.
 
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