Quadrajunk on a 235 intake

I have an old q-jet off my car and have been doing some reading on them on 230 ci sixes and kinda want to do it to my six and is it possible to cut out the center of the factory intake and have a q-jet flange on a small riser welded to the plenum? And I am looking at a set of speedway tube headers for it as well

 

unless you know someone who will change your intake for free i think you would be better off looking for another intake. Clifford makes one

 

It's an interesting idea. The Q-Jet primaries are a nice size for smaller engines and the Pontiac OHC 6 used it in the warmer versions. I just wouldn't consider using the big Quadrajet that's rated like 850 cfm on a V8, as it would be way big for the application.

Can you fab the new center section for the manifold, then have it welded in?

 

That was my plan was to build my center section then have my local welder install it and I have two factory intakes but is it possible to convert them to water heat aswell

 

There's a pic of the Clifford water heated manifold at http://www.jalopyjournal.com/forum/showthread.php?t=646575 that may help your design. I think Clifford manifolds are made to run with headers, not stock exhaust manifolds, so no stock intake heat.

EDIT: The pic shows a fairly long pipe inside the intake, wider than the carb by a few inches. I have to think there's a purpose for that, maybe increased contact for better heat transfer.
Langdon's site has a small writeup about manifold heat, if you haven't seen it yet.

 

This is a picture of a Willies manifold i turned upside down and opened up the exhaust hot spot to allow a four barrel to be bolted to an adapter. Maybe you can do the same with a 235?

 

Excellent idea, Rich! (There it was all the time...just had to look 'outside the box'...)

 

As a 15 year GM Driveability tech (70-85) I love Q-jets, but i think a Autolite/Motorcraft 4100 might work a little better. They do a really good job of atomizing the fuel. That makes it easier for the Heat to vaporize the fuel and get it to the end cylinders.

Hoop

 

Rich, that's a foxy idea. Even if the port flange isn't symetrical when flipped, there's nothing to stop a guy chopping out the whole center section and flipping it, then welding back in. That would give a nice big area to mill flat and fit a big carb flange.

 

Now there's some cool Chit!

Either way you go on your six, a length-wise baffle should really help fuel distribution from favoring the center port.

And water heating will be a snap, either way. Just make a plate, and plumb it for hoses taken from a tee on your heater hose. (If you flip the manifold as above, just block off the old carb intake, and use it for your heat chamber.)

There used to be a carb (Holley ?) that fit a spread-bore manifold, but flowed about 500 CFM. This may be well suited to your needs. An AFB flows about the same.

 

This is the Holley Economaster 450 CFM, back in days of the "Jimmy Carter gas crisis" these were good for about 2-3 MPG over a stock Quadrajet on a bone stock car.http://www.ebay.com/itm/ORIGINAL-HO...-450cfm-ECONOMASTER-CHEVY-MOPAR-/190858247423