Rochester 4MV
Pro
Joined: Jul 2004
Posts: 689
Likes: 1
From: Media PA
My advice...after 35 years of changing 4MV's (15). I gave up. Just put on an Edelbrock 1806 Thunder & performer intake. My car has been original since new, but I just couldn't take it anymore. Now the car runs better than new. 
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,307
Likes: 1
From: Milford Haven Pembrokeshire
Why did you have to keep changing them - worn out or what ????????
I am used to carbs lasting the life of the car with maybe a rebuild along the way. ??????????
Now more confused.
Chap here in UK has a 4MV off a 1982 Pontiac 305 which he's selling cheap........ shall I get it .???
I am used to carbs lasting the life of the car with maybe a rebuild along the way. ??????????
Now more confused.
Chap here in UK has a 4MV off a 1982 Pontiac 305 which he's selling cheap........ shall I get it .???
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Originally Posted by hensen1954
Why did you have to keep changing them - worn out or what ????????
I am used to carbs lasting the life of the car with maybe a rebuild along the way. ??????????
Now more confused.
Chap here in UK has a 4MV off a 1982 Pontiac 305 which he's selling cheap........ shall I get it .???
I am used to carbs lasting the life of the car with maybe a rebuild along the way. ??????????
Now more confused.
Chap here in UK has a 4MV off a 1982 Pontiac 305 which he's selling cheap........ shall I get it .???
Get Doug Roe's Rochester Carbs book, mainly about the Q-J & you can know more about the Q-J than 99+% on any forum.
Tech Contributor
Joined: Aug 1999
Posts: 14,377
Likes: 6,376
From: At my Bar drinking and wrenching in Lafayette Colorado
Hensen -
You can't use the '82 Q-Jet on a Vette. It requires an ECM, and cannot be operated "manually."
I have found that the 1975 - 1979 Chevy Q-Jets are about the most versatile. These are in cheap abundance, and they can easily be converted to electric choke by installing a 1980 choke cover. Drawback to this style Q-Jet is that the primary metering rods are only available in a few sizes.
The 1969-1974 Q-Jets are a bit more tuneable, and all rod sizes are available still. This vintage carb uses a divorced choke system that can only be converted to electric choke by using a manifold-mounted electric choke coil.
All Q-Jets, regardless of vintage, are about 750 cfm (with a few exceptions).
You can't use the '82 Q-Jet on a Vette. It requires an ECM, and cannot be operated "manually."
I have found that the 1975 - 1979 Chevy Q-Jets are about the most versatile. These are in cheap abundance, and they can easily be converted to electric choke by installing a 1980 choke cover. Drawback to this style Q-Jet is that the primary metering rods are only available in a few sizes.
The 1969-1974 Q-Jets are a bit more tuneable, and all rod sizes are available still. This vintage carb uses a divorced choke system that can only be converted to electric choke by using a manifold-mounted electric choke coil.
All Q-Jets, regardless of vintage, are about 750 cfm (with a few exceptions).
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